The point is not that there is nothing to learn after 8-10 years. There is enough to learn for multiple lifetimes. The point is that after 8-10 years additional learning/experience will not give you a competitive advantage compared to younger programmers.
Also, I can see why someone would downvote my post above, since it describes an unpleasant reality. But I think it is crucial for young programmers to be aware of this dynamic!
You're getting down votes because it's simply not true. It's not about age it's about the person. And it couldn't be more wrong to say that there's nothing to learn after 8-10 years, even in web.
But let's talk about the competitive advantage part of your argument.
Personally, I have spent 20 years collapsing and simplifying "everything" in my work product. IE ui design, coding patterns, and all other aspects of my tech related work product.
Whenever I show my code to new devs they usually say "yup I get it, it's easy". But it's not easy, I just spent a crap load of time thinking about those patterns over the years making them easier and easier over every iteration.
So, that's one competitive advantage right there.
But another competitive advantage polyglot old guys have. They can truly be a full stack developers taking an idea from mockup to web and mobile and completely scaled distributed systems.
It's VERY hard for anyone to do that without putting in 10-15 years because each discipline (design, mockup, mobile, architecture, scaling, etc.) takes a lot of time and effort to master. That said I have met 30 year olds who started at 15 who could do that too.
I think of it like the CEO who worked his way up from the mail room, he's seen every part of the company inside and out and that's why he's so good at building companies now.
Look, I agree with your suggestions. But each of the things you suggest (improve yourself, become full stack, maintain mental elasticity) falls in the category "try harder". That only works with things you can control.
There are also things you cannot control - changes to your brain as you get older, the kinds of jobs that are available, what other computer programmers specialize in. These are your odds.
Your success is a function of your efforts and your odds. Success = f(try harder, your odds). Since you are human, you can choose your path, and it doesn't make sense to choose a path where the odds decline so dramatically as you get to 46 ... 58 ... 63 ...
Sure it does (at least, as much as any other "intellectual" field, like accounting or law). Do you want the guy who knows X (or 3 variants of X, each sequentially in fashion)? Or the guy who knows X, Y and Z?
The key is, no matter the age, to keep expanding your knowledge base.
Well, different intellectual fields have different experience curves.
Accounting, medicine, law all have much longer experience curves. Accounting also has significant barriers to entry (though not as high as medicine). Law has lower barriers to entry and you can see them facing a wave of unemployed lawyers and closing law schools right about now. Etc ...
Also, I can see why someone would downvote my post above, since it describes an unpleasant reality. But I think it is crucial for young programmers to be aware of this dynamic!