I'm not sure I agree with that reasoning generally, but specifically this is IMO not quite true:
> The whole Github/MIT licence scene simply did not exist back in the days, it was either closed source or GPL.
BSD-licensed software, and probably also MIT-licensed and whatever non-copyleft licenses there are, has been a thing for a long time. I distinctly remember seeing discussions and opinions regarding copyleft vs non-copyleft open source in the early 2000's. Aside from BSDs themselves, there have been all kinds of non-copyleft licensed software all along.
It might be that more liberal (i.e. non-copyleft) licenses have been gaining more popularity and that the emphasis has moved from GPL to non-copyleft licensing. It might also be that's partially driven by the dominance Google et al. have on tech culture. But as a whole I'm not sure that hate (if it exists) towards GPL-oriented culture follows from that.
As a stab in the dark, it could also be that there's a new generation of people for whom the older days of the GNU project and the free software movement sound somehow archaic or "not modern" now, or there could be some other kind of a cultural shift. People don't always embrace newer trends because of some kind of a clear economical or other direct motive.
Economic interests of the current powers that be might of course be one of those things that affect cultural changes, but I wouldn't necessarily buy it that it's the only reason.