And personally, as someone who grew up in the 80's, let me offer up a counter-anecdote: I don't ever recall hearing a "fast-busy tone". There was never a time we couldn't use our land line (at least until we had a modem, that is).
1) In the event of a major disaster, you've probably evacuated. You can't take your landline with you.
2) Telephone poles burn.
3) Even if the cellular system is completely hosed, you might still be able to get on a data network. All you need is crappy wifi anywhere (cafe, hotel, friend) and you can get an email out.
1) Not all disasters can be evacuated away from. Tornadoes, for example.
2) So do power poles. And those telephone poles are also probably carrying data.
3) You can't dial 911 via email.
Cell network congestion is a well known phenomenon when disasters strike. It's been seen multiple times in the past. Yes, landlines can and do fail as well, but they're more resilient than cellphone networks.
Perhaps this will flip in the future, but it hasn't, not yet.
2) Yes, power goes out too. Cellphones have batteries.
3) Yes, you can dial 911 via "wifi calling". I've done it.
I don't know about "hate" but I do think landlines are overrated. You already have a cellphone. Paying for an extra service and apparatus for the tiny possibility that you need to call 911 when your cellphone can't - why? Who else are you going to call? Do you even know their phone numbers without your cellphone?
I also think you're undervaluing cellphones by assuming they only talk on the cellular network. You just need to get on a data network somewhere and you suddenly have a wide variety of communication options, including phone calls. TCP/IP was designed to withstand nuclear war.
You generally have some charge on your phone, though, and lots of folks have power banks now - or cars they can charge their phones with.
Don't forget all the times when disaster strikes and the cell phones are a real help: Car accidents, for example. At one time, you were reliant on you - or someone else - stopping by a house and hoping they'd be home. And I'm sure there are lots of other examples of this as well. Now that laws changed, cell phones can pretty much always call 911 as well, even without service at all: This was not the case with phone lines. If the house didn't have service, you couldn't get help.
Crucially, however, there is no profit in getting to the point of being properly provisioned for emergencies, and no regulation pushing for it. Land lines, in contrast, are regulated to push for availability during emergencies.
I got fast busy tones several times a year back in the 80's, and it usually corresponded to whenever a concert was announced. Maybe my phone company back then was as bad as your mobile services company is now?
There’s a lot that still sucks, but I don’t miss landlines the slightest bit. Scheduled do not disturb is a godsend next to trying to remember to turn the ringer on the landline in the hallway off at night.
I think most people don't realize why phone calls suck these days; it just feels awkward and cumbersome, but it doesn't have to be that way.