I think ageism in tech will mature along with the industry as well, that was the first wave and a very disruptive one, so this generation has disruption as a modus operandi.

Back then old meant something different as it was a new industry, older people didn't grow up with tech and there was a huge valley/difference between someone that gets tech and a generations before that didn't have it. Everyone below 40-50ish (and definitely everyone in their 30s and below) has had tech around their whole lives and at a more core level as it was new and attracted mainly young people then, but now it attracts all people and has had people working in it for decades (past mid 90s when the internet went mainstream, most are still doing it).

I have to say working for over a decade in tech/programming that most of the really good programmers were over 30s (and all good product developers were either close or over 30), this is because it takes 10 years to get good at anything even if you start in your teens, shipping products for 10 years can't be sped up. Someone out of college at 23-24 needs to work until 33-34 to be really good. To discard that is futile and young programmers might even be scared away from this line of work if there are no future prospects. I also believe it will be detrimental to our entire country as technology is so important now.

Funny enough in game development some of the best I have worked with were actually in their 40s nearing 50s even though it is also seen as a young industry, game companies wouldn't ship anything without experienced developers of 5-10 years, you can't get that experience and then be worthless at 35.

When there is a new industry, the people in it at that time sometimes gain more valuable lower level experience because the platforms/layer is still being constructed. So engine developers that are older were almost always better than younger because they have the core knowledge without the layers of fluff that product cycles can add. Just like back in the day hardware was more prevalent and a population of people that were in it then are sometimes better at it because they were around when it was big.

The market is also solving ageism by paying programmers better than managers many times. Noone will desire to go manage if it is a step down. There was a temporary moment in time when there were NO development managers, sales/marketing/bizdev couldn't manage it. So they NEEDED programmers to go into management to make sense of it and they are good at marketing so it stuck in the collective psyche. That has changed dramatically and I believe this will mature the industry.

Also, let's not confuse ageism for VC funding selectiveness, they will always choose younger because the term sheet is easier with younger that are less knowledgable about value. The 'problem' with older coders is they know they can ship and know their value.

Who knows, if the WhatsApp guys were younger Facebook could have gotten it cheaper. If older developers build more value, VCs will see they can flip for higher amounts and that may also help this perception problem.

Ageism isn't just a problem for older developers, it is a problem for younger developers as well in that they are smart contributors that will be shut off after 10-15 years of solid work, right when most of them will be in their prime and contributing to society.