Around 1990, the development tools offered by Borland and Microsoft for C and C++ were pretty much equivalent and they both were quite good.
While the Borland languages were like "Turbo-X", the Microsoft languages were like "Quick-X".
The greatest difference between the commercial software available at that time and what exists today is that everything was accompanied by a set of high quality manuals that could teach you anything that one would want to know. Nowadays the quality of technical documentation is usually much worse.
Default keys in modern IDEs are basically still the vs assignments from the 5/6 era.
It was the closest Microsoft ever came to making their own emacs or vim. vs6 was like 90% of my screen time as a windows dev in the 90s and 2000s
I've been a linux user for 30 years ... I never had the vs6 level of efficiency in linux, still don't. NetBeans was the closest ... yes, NetBeans... (I've given up though, I do things in nvim, tmux and suffer)
(A nice thought-experiment is to ask if Quake could have been coded in TP at all - even if memory hadn't been an issue (I think there was no DOS extender for TP, but I could be wrong).)
So Turbo Pascal (with a whole bunch of x86 asm inclusions) was totally capable of producing Quake-level games. I myself, in the late 90s, discovered the hidden capacities when I learned x86 assembly from Peter Abel's book. Once I got rid of the primitive TP BGI library and switched to VGA 13h, it was an unbelievable level up in abilities to manipulate pixels on the screen!
I might be misremembering but I thought it was more of a Doom-style engine with 3d models instead of sprites for the entities, rather than a full 3d engine like Quake.