Except that along with MS-DOS, it put a PC in every office
No, IBM did that. Personal computers (non-IBM, non-Microsoft) had been around for a while already, but not in mainstream offices. That is because company IT buyers at the time would not buy anything without the IBM logo on it. The IBM PC made personal computers respectable to business because they were IBM, it would not have mattered what OS they ran (could have been CP/M-86, IBM could have written their own, Seattle Computer Products* could have provided DOS directly instead of via Microsoft, or whatever). Also, IBM PCs could be used as terminals to the company [IBM] mainframe so the clueless company buyers could be fooled into thinking the IBM PC was no more than that : that is how my office first got one.
and eventually a PC in every home
My home had a personal computer before the IBM PC with DOS was invented, and before I'd even heard of Microsoft. The young guys I worked with also had Commodores, Sinclairs etc. Home computing was taking off already without IBM/Microsoft's help and would have gone to the level it did with or without Microsoft
without which Linux might not have been possible.
That claim, sometimes heard, completely baffles me. Are you saying that personal computers would never have developed the power to run Linux if it had not been for Windows? WTF wouldn't they? Linux runs and is developed on almost any platform. It was originally developed on Minix, another Unix OS. IMHO Microsoft retarded the development of the PC by about 5 years while they had their love affair with Windows 9x.
* You do realise don't you that DOS was not written by Gates or Microsoft, it was bought by them? They hired the author (Tim Paterson) to port it to the IBM PC.