You could technically program without it in standard event loop, but then the code would have been unfamiliar enough to other Delphi developers to perpetuate some of the same issues.
Not everyone was using OWL all the time.
I got my professional start using Delphi, but never got the impression that many of my colleagues knew TPW well.
Of the ones that didn't come from a database or 4GL background, most of us had used BCW for Windows coding and then switched back to Pascal when it became commercially viable to get a job in it. Borland Pascal didn't exactly have a ton of play in 1995. So it's true that they would've understood basic Petzold-style loops, but it would've been a bit surprising in Delphi.
Later, most of the people I knew using Delphi didn't know bare Windows programming at all, since MFC had fully taken hold for people from that background.
I was also under the impression that OWL was quite dominant, but I admit that I only passed through it briefly between Turbo Vision and VCL.
Still, good point!
And I think you mean Modula-3, not Modula-2.
It's kind of a shame. I'm a huge fan of languages like D, Modula-3, and Delphi, and I'm really disappointed they never took off.
All strong in the 90's, sadly the market went somewhere else.
Only Ada seems to survive, but in its own area, high integrity computing.