"Skills pay the bills." Generally, the kind of people you want to work for (by the time you're 40-50) will not give a fig about your age if you can deliver.

Here's the thing about being an "old" programmer. If you can't keep up with the newfangled shit, then you probably shouldn't be competing against younger programmers, because at skill-level-parity they will beat you on speed and total hours spent, eh?

For example, the fact that FP is finally making it into mainstream development shouldn't throw you if you have had twenty years to experiment with e.g. Haskell, eh? The only thing close to surprising in decades is how well backpropagation works when you have hella data and CPU power.

By the time you have been programming computers for twenty years, you should be really good, or you're just a "jobber". There's no shame in that, the world needs jobbers, but yeah, just like in wrestling, there are very few old jobbers.

If you're not a jobber, then at some point you see through the fashion-driven parts of the IT ecosystem and figure out what you really want to do with yourself. At this point a lot of people switch to management, or start their own company. But that leaves the field (of programming) to the die-hards that really give a fig about it. So if you're still in the game, late in life, and you're capable, then yes, there is high demand and you can e.g. command hefty salaries.

(Disclosure: I'm 45 and employable.)

I myself am 40 and am gainfully employed and paid well in a top SF tech company, I have several mid to late 40s friends who are highly paid and appreciated at their jobs and have turned down offers from FAANG. I think the key is realizing what more jr engineers able to do well and compete at something else, like depth (or extreme breath) of knowledge, soft skills, organizational skills, and of course leadership.

I'm over 40 - I found myself suddenly back on the job market a couple of years ago when the company I worked for abruptly went out of business. I was only out of work for three weeks before I found something else. I keep current, though - one of the realities of this profession is that you have to keep learning, and you have to do it "on your own time", if you want to stay in it. Personally, I find that to be a reasonable trade-off, but I know a lot of people don't.

The $64,000 question is "Does the experience and skills that you have as a 40+ year old make you worth hiring versus a junior developer or fresh graduate?" Unhappily for a number of people, the answer is "not really".

This is not a profession in which one can coast. Every year in which you're not learning something that makes you a better and more capable professional, whether at your job or on your own time, is one year in which you're falling behind the rest of the pack.

In general if you don't keep up with the pace/trends, you will become out of touch. I would suggest this is for programmers that stop learning while they age.