Later I got a Spectrum; later still a PC. It was vital that these came with BASIC. Paying for development tools would not have happened. Eventually I acquired pirated copies of Turbo Pascal, Microsoft QuickC, and finally a legitimate but already obsolete copy of Borland Turbo C on seven 5.25" floppy disks.
Eventually I also got a modem and could gain access to such troves as the PC Game Programmer's Encyclopedia.
I think the main difference is that if you came up with a question you had to answer it yourself through research or experimentation. If you weren't very persistent, or weren't given the free time to do the necessary self-directed learning, you wouldn't get very far.
Modern knowledge is streamed to you in small fragments. Back then it came in lumps. Multiple-inch-thick lumps. Most of the books were pretty worthless, although the Peter Norton ones I really learnt stuff from.
It was also viable to set out to read the documentation you had cover-to-cover and go looking for interesting or useful things. These days there's almost too much, and it's certainly not linearly structured.