There was a wave of 8-bit interest from 1980 onwards, with the ZX80/81, ZX Spectrum, Electron, Dragon, and other cheap machines. The BBC eventually caught up with its own micro, but it was between and four times the price of other machines, so it was only ever bought by very rich parents and universities. And a few schools.
These machines were all zero-setup hands-on BASIC environments. A lot of people used them for games, a smaller number typed in listings by hand from paper magazines, an even smaller number learned assembly programming.
It was incredibly easy and cheap to set up a games company. You wrote your game (hard - but not that hard), you paid a relatively small fee to have some tapes duplicated, you put an ad in the back of one or more magazines, and when the orders came in by post you sent them out by post. Marketing? Send games in for review and maybe hire a stall at a computer fair.
If the game was even slightly better than average it would sell.
The result was that anyone born between around 1960 and 1970 had cheap access to good-enough hardware on which to learn simple programming and a ready-made business model they could copy, all requiring next to no start-up capital.
There was a shake-out in the mid 80s. The PC arrived and business-ised the market, raising the cost of entry. Games became more challenging to develop as graphics techniques became more sophisticated. The 16-bit machines arrived, which took things up a level as dev tools started to cost real money.
So by the 90s the scene was an industry. Schools were largely irrelevant to it. Some schools had "computer clubs", and the BBC had promoted BASIC for a while, but in 1991 8-bit BASIC started to be replaced by VB, which wasn't a school-level topic. Windows 3.1 programming was hugely more complex than either BASIC or assembler and the tools were insanely expensive. By now the cost of entry was far beyond the resources of most teens/students, and alternatives like Delphi (Pascal) couldn't sell directly to schools like Microsoft could. And even if they could, most parents weren't going to buy their kids a PC to play on, because PCs cost as much as a car.
Schools taught Office because there was no longer a useful entry-level for developers. And anyone who'd been up through the 80s was now working as a developer and getting paid a lot more than they'd get as an ICT teacher.
tl;dr the industry cut out the educational system. "Business-ising" the technology starved a generation of access to affordable computing and the high cost of entry made it very difficult for talented teens to build the next generation of businesses.