Becuase it was a typical MS user experience. MS was shipping their software on 25+ install floppies. Having an install fail on floppy 19 was a nightmare. Getting a fax modem that shipped with the PC to function could also be a problem MS would blame the vendor and the vendor blamed MS. It’s not like his moviemaker experience was a rare occurrence.

People forget the "if Microsoft invented the iPod" parody video."

https://m.youtube.com/watch?v=yvh5k1RWER4

It describes the culture of both companies at that time very clearly.

I think the difference between Apple and Microsoft is that Steve was a "product" CEO. He would bot only send that email, but in addition he would somehow oversee/sypervise those changes ALL the way until he was satisfied.