What are you talking about? The average person may not be able to solo mine a block but you can still earn meaningful quantities through pools.
One of the potential benefits of the scrypt algorithm used by Litecoin and Dogecoin (and others) is that even with scrypt ASICs being developed, the memory-intensive nature of the algorithm has so far prohibited a massive disparity in hashing ability. You can still buy a sub-$2000 mining rig that will basically pay for itself in a couple months.
No you absolutely can't. About 6 or 8 or so weeks ago I was making about $4 a day mining scrypt coins. Now I'm making $1.50. I don't think it is going to be profitable 6 weeks from now. When Dogecoin first exploded I had several $15-$24 days. Right after I first started there was actually a graphics card shortage(!) because of the interest in mining.
My graphics cards haven't been paid off yet with just mining, and I don't think they will be. That's not a problem for me, because I can sell one of them, and keep the other, which will pay them off.
If you don't already have the PSU, CPU, MOBO, etc, you are wasting your money building a mining rig, especially now the profits are so low. Only buy a graphics card if you want the card for other reasons. Those mining profit calculators way way way overestimate.
EDIT: My system has 600 kH/s hashrate.
EDIT EDIT: Even 6 or 8 or so some people on the litecoin mining subreddit were very confused about people who were building expensive mining rigs and pointing out how those rigs will never pay for themselves.
altcoins cannot be forever profitable as basic economics tells us this.
Pretty simple economics but kind of scary for a system which is based around mining.
The answer would be "because bitcoin is legitimate and dogecoin isn't" - but I'd argue that bitcoin hasn't gotten there yet. So it's a race, and one that any cryptocurrency is likely to lose.
For a single novice user this would be the cost of hardware (substantial), opportunity cost from delays in delivery of hardware, decaying returns with exponential increase in difficulty, cost of electricity and opportunity cost.
Then it needs to be ascertained if they are mining a commodity or an investment. That is mining to sell (similar to farming and mining minerals, metals etc.) or are they looking to hold it for long periods expecting an appreciation. The later has other practical implications.
For the majority of prospective miners, these costs are huge and have little to no chance of breaking even.
Arguments could be made for or against the profitability from speculation/long term holding, but that is beyond the scope of most people's definition of meaningful.