It's the opposite. Few companies know that you can do without PR. Even fewer know why they are doing PR or where it comes from. But everybody starts with PR, it's the default in their VCS UI.
I described my experience and what I saw, well I did not do any scientific research on 1000s of companies. But I still think my experience has the same validity as your statement. So it can be both at the same time, there is so many companies small and big.
Ok, let's say a lot, or most, companies use processes without knowing why.
Some might just push commits without knowing or caring about reviewing code, beyond fixing what fails in production. But others might just do "git flow" or whatever, doing thorough PRs, without knowing that the changes could be requested after being merged and without realizing the amount of time that is wasted on integrating code and re-testing.
In particular, I think that PRs come from an open source model, where you really have to gatekeep. But in a company, there is no problem in following up: the devs are salaried and you just need to put them to work on whatever is necessary.
