Totally of the same persuasion as you, I'll say I did hear a very good counter point when Magnus Carlsen said in an interview at 30 he feels he can't compute lines as deep as he could previously, and his edge is now his experience. That was rather convincing.
Most of the folklore around "neuroplasticity" I've found pretty underwhelming. But yeah, if even he says it at that level of consistent practice, that seems like a good yardstick.
As I've experienced getting older I've found it's more about the lack of available time and focus.
I don't have the hours of time a young person does and I don't have the focus, there are a lot of other thoughts, emotions and responsibilities competing for my attention.
Would love someone who's aware of the literature to throw their hat in the ring though.
Big companies drift away from the ground truth of their employees and customers over time. Without someone highly focused coordinating things, it's easier to create a "new" product and call it a day than it is to innovate.
And when you're big it takes years, decades even, for the cracks to eventually show, but show they will.
Because ask yourself, if you were telling your friend to buy a Macbook, which one would you tell them to buy?
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edit: just to clarify, currently Apple's lineup includes the "What's a computer?" iPad – $349+, iPad Mini - $500+, iPad Pro – $999+ and iPad Air – $599+.
These come with a pencil and a magic keyboard. Also some of them are more powerful than the A18 Macbook Neo.
Then there's the Macbook Neo - $600+, 13" Macbook Air - $1,099+, 15" Macbook Air – $1,299+, 14" Macbook Pro – $1,699+, 16" Macbook Pro - $2,699+.
Who are all of these things for? Why does the iPad Air exist with the magic keyboard alongside the Macbook Neo? That's the same keyboard attached to a less powerful processor and a touchless display for a spitting-distance price.