There are multiple eras here.

MS missed the tpc/ip train completely and ended up just copy pasting the stack from one of the BSDs in Windows 95 I think, or it wasn't a default install, I forget which.

They were late to the http train and had to give away explorer for free. You can tell how desperate they were since they didn't do the same thing with office.

Then between 1999 and 2012 they completely dominated.

Then they missed the mobile train completely and lost the browser wars. And here we are.

I blame IE being free for the state of the internet we have today. If people were trained to pay for it then we wouldn't have spyvertisment as the only model for it.