Love or hate, Microsoft certainly did a lot to empower hobbyist and professional developers in the PC/wintel era. Certainly in the 80s SDKs were notoriouly expensive. OS/2 dev kit was $3000. I remember the SGI Irix Developer Option (IDO) was $3500. you could get a C compiler from MS for about $500.
MSDN later become something pricey but wasnt strictly needed to sit down and build code for a PC and ship it
I think SGI's hardware was exclusive enough to limit their audience anyway, but everyone else, including Apple, really screwed themselves with this.
This is something Steve Jobs fixed at Apple in 1997 by eliminating per-division tracking of profit/loss. When the VPs are freed from profit motive for their direct divisional output, they become responsible for the profit of the entire company. It's worked pretty well.