There was a good Miyamoto quote regarding this when Legend of Zelda Ocarina of Time was continually delayed.
"A delayed game is eventually good, but a rushed game is forever bad."
That was 100% true in the days when you couldn't patch on day one and had to order expensive cartridges to be produced, the irony despite being a fantastic game OOT was eventually totally broken by speed runners, so even that shipped with multiple bugs. Miyamoto's words are not completely true now with patches even on console, but it does still apply to a lot of aspects of game production.
The PC version is finished, no doubt, but they won't risk touching a damn thing about it in this 21 day delay in case they introduce even more bugs. So it'll just sit there until the consoles are finished and then get multiple patches within a few months.
Piracy is why we can't enjoy the PC version first, CDProjekt cannot risk potential console buyers pirating the PC version instead. I don't like it, but clearly having console releases first is better business sense as many will double dip upon the subsequent and superior PC release.
As for crunch time and overworking staff, I don't how CDProjekt thought they could ever avoid that - they're big boys now and they'll have to wield the same rod that the big boys do to get games released, IE; art and programming staff being worked like crazy so management and executive staff can profit.