It's not complicated: the costs of software development are almost entirely in labor. As long as that remains true, older people will be at a severe disadvantage simply because they cost 2-5 times as much as a new hire. Once Moore's Law slows down (or whatever we want to call the current golden age we're seemingly still in), this will change, but until then you're just fighting against exponential growth.
But that would be folly long term.