I remember having a 386DX-40 during my later years in high school and off into college. I was teaching myself C++ and x86 ASM in HS. That's what I was using a computer for.
Nowadays, kids just want to YouTube.
My theory on this is that roughly the same percentage of people that "needed" a desktop back in the day, the 1 out of 30-40 folks like yourself who was teaching themselves programming and so on, is roughly the same percentage of folks that need a desktop computer now.
In other words the base level of demand has always been there, then and now, and will be going forward.
What happened in the meantime was a bubble in the demand for desktops which was solely fueled by everyone else who only really wanted a computer for the internet connectivity stuff - email, google, youtube, pic sharing, IM.
All that stuff was the killer app for the desktop market but only because the desktop market existed and had products to sell at the time. Had the mobility offered by today's smartphones and tablet form factors been available 20yrs ago then the entire desktop market revolution would have been sidestepped in my opinion.
In this hypothetical timeline, workstations for the professional would still have happened, and laptops for the professional still would have happened, but the TAM and market volumes would be 1/10th their current volumes.
At least that is how I see it when I look at my family versus myself. As soon as smartphones, tablets (iPads), and the e-readers like Kindle came along, every single one of my family members jumped ship and hasn't looked back.
I used to buy them all desktop upgrades and new builds, every other year. Then it became all the rage to buy laptops instead, not a desktop among them. Now I haven't bought a laptop for a family member in years. Since 2010 or so. But they all have (and really do use) all these other tablet and smartphone form factors.
And here I am, still using desktops and laptops, the 1 in 30, and probably won't ever give it up.