I predict that this will blow over, and won't be a big deal in a few years time once FOSS drivers for what is effectively just a new breed of TPM are released.
If in five years, it turns out I was wrong, I'll eat my hat. Although defining "my hat" by then might be difficult, as it'll probably be subscription based.
Oh hell yes they did. Look at Intel Boot Guard and all the stuff around that.
what am I looking for? It looks like you couldn't load third party/modified firmware with that enabled? I suppose it's strictly more locked down than being able to flash whatever firmware you want, but was there a sprawling scene of modified firmware around at that time? Or did everybody essentially run the stock firmware?