If any crypto currency ever makes it and becomes mainstream, then I am pretty sure it will not be Bitcoin, to many unsolved or even unsolvable problems. If that turns out to be true, then the question becomes whether we already reached the final decline or whether the speculation will continue. Personally I don't think we have reached the final decline just yet but at the same time I find it hard to imagine that Bitcoin will ever reach $100k or so, people are probably slowly becoming sane again. If you hope to make as much money as some did by getting in at $0.10 and exiting at $10k, I think the chances are pretty much zero. Maybe you can double your money or get 500% if you catch the bottom of a correction but you may as well lose everything.

In the previous 3 bubbles bitcoin stabilized after the crash around 2-3 times the top of the previous bubble.

So applying this logic, the bottom of this bubble should be around $2-4k. For a couple of reasons however this bubble is different - lots of finance guys participating. Because they are experienced they will buy ahead of that to make sure they don't miss the bottom. So I see this bubble bottoming at $5k. This has the nice property that most of the "dumb money" who entered in Nov-Dec without any idea about trading or cryptos will lose money (markets tend to make sure that people who entered during a frenzy lose).

There is no floor on Bitcoin's value.

I would buy more at 1k even though I don't really believe in it. Just because of the volume of people and brainpower being devoted to it. Basically I would be hedging in case I'm wrong (which is is a frequent occurance).

Before I begin, I'm not going to tell you what to do with your money. But when I see questions like this, I often think that there may be some inexperience with investing. So here's how I look at investments. This is not advice -- you do what you want.

If I'm investing in a company, the first thing I do is read the quarterly and year end reports. I take a look at how the money is being used. I look for things that might be fishy. You need to be careful, even with blue chip stocks -- often the numbers don't add up. I look at how well the company is executing. What kind of margin are they getting? How are they using that money? If for growth, then what are the investing in and how well is it paying off? If for profit, how much profit are they making and what are they doing with the profits? That kind of thing. I look at the products they make. I read reviews. I look at the competition. After I've done all that, I decide how fairly the company is valued. Often they are over valued. Sometimes they have about the right value. Rarely they are undervalued. I try to buy the latter stocks and hold them for a long time.

Just because of how I do my job (I am a internationally remote contractor), I am forced to speculate on currency. Note the subtle change in vocabulary. I am not investing in currency. I don't expect a rate of return over time on currency. Instead, I look at geo-political situations and I guess how it might affect the price of a currency against another currency. At the moment, I live off the Japanese yen (I'm in Japan), but I get paid in Great British pounds. I need to have some insurance that my revenue stream is relatively constant, so when GBP is very low (it was down to just over 120 JPY last year!) I try to hold it. When it is very high, I try to sell it. Sometimes it makes sense for me to even buy it when it is low. When I am looking at this, I look at both the British and Japanese economic policies. I look at elections that might change that policy. I look at the (complete lack of) progress wrt Brexit, etc, etc. But this is not an investment. My goal is to hedge against the changes as much as I can, because otherwise sometimes I'm working for 60% of the wage that I normally make (and it's hard to ask your clients to double their payments just because something like Brexit happens).

Now, let's look at Bitcoin. What economic factors influence Bitcoin? It would be tempting to say "none", but this is not strictly true. First, we have to look at the likelihood that bitcoin will become viable as a general currency. It's pretty unlikely, but the chance is not actually 0 (Much to my surprise, I can actually buy things with Bitcoin from mainstream shops in Japan -- even a local pizza restaurant takes them). However, it's clear that changes to the protocol need to happen for it to scale. To understand the implications, you have to understand the chances for various proposals to succeed (both technically and politically).

When you look at trading currencies, often you look at indicators like interest rates because the change of interest rates encourages (and sometimes outright forces) trading of the currency. With bitcoin there are precious few outside influences like that. There are things like "tethers", but since they are a complete scam you have to figure out what it's likely to do to the price (will it force people to buy BTC, or will it tank the price).

Having said all that, I hope you can see a kind of gradation in the "investment" type. When I buy stock, I can reason about the performance of the company by looking at their past performance, their execution, their product, the oppositions performance, etc. When I engage in FOREX (which I try to avoid, but alas am unable to), I am stuck with the politics and economic policies. I have to kind of guess what countries are going to do and how that will result in changes to the price. I try my best to stick to hedging strategies, because otherwise you might as well be laying bets at the bookie wrt economic policy. With Bitcoin, it's just gambling. The price swings are generally due to hype, scams, and bad actors -- with only a little bit related to potential viability. And I would say the the long term viability of BTC as a whole is pretty long odds (remember, this is not advice -- decide for yourself).

So if you want to gamble, then gamble. I'm not going to stop you. But I don't think you will get any useful advice on "investment" in Bitcoin. It's just not that kind of vehicle.

When the price is less than expected future returns from the 'investment'...

I've discussed this with some analysts who are looking at the cost of mining hardware and also power consumption/costs. They concluded that around $5k is the appropriate target price right now.

price can be irrelevant. i have mates that buy on one exchange and sell on another right away. they make weekly on the difference. some cap you at what you can buy/sell and increase what you're allowed each time. with a few $k you can make $150 a week. i.e buy on coinbase if that's cheapest. transfer to another another exchange and sell. bingo. few of them been doing it for months.