I don't know if you're thinking about all the millennials or just a few. PCs weren't as common in the early 90s.
My view is certainly skewed since we had a 386SX, but there were tens of thousands of BBS's running back then. Online services exploded in the early 90's, shareware games like Doom and Wolfenstein sold hundreds of thousands of copies. In 1992, Gateway 2000 surpassed Dell by selling over a billion dollars in PC's.
My kindergarten classroom had an Apple II in 1989. Our first grade classroom had old IBM PCs.
My parents bought our first computer in '94 and we were one of the later families to have one (these were actual middle class families).
I too am quite fearful of the fact that I know zero kids under the age of 15 who have any interest in learning how computers work, despite being completely surrounded by them since age 8 or 9 (via school-issued Chromebooks).
Now I do know a lot of kids under 15 doing computer tinkering, usually gaming PCs. If anything, I'm worried that they do it too much.
Spectrums, Commodore, Atari, Amiga, PC, Acorn, as home computers ecosystem surely.
At least in Europe we weren't that much into consoles, having a home system was one from the list above.