You mentioning Delphi reminds me of the Miniatur Wunderland in Hamburg, a large model railroad with a day/night cycle, cars driving on the roads and planes "landing" and "taking off", a lot of it controlled with Delphi: https://www.embarcadero.com/case-study/miniatur-wunderland-c...
I dont even want to imagine how that codebase looks. The delphi code I‘ve come into contact with (not a delphi dev myself but worked close to them) tended to be quite bad by modern standards. The reason why was generally similar: not very experienced devs in the 90s needed to something with a UI off the ground.
Its true. I think the brain drain has had a severe impact on the evolution of the language as it exists in Delphi. However, some implementations, such as Oxygene, appear to evolve rapidly.
The fourth thing is that it lives on as Delphi:
https://www.embarcadero.com/products/delphi
And there's Free Pascal and Lazarus. One of the goals of Free Pascal is to be Turbo Pascal and Delphi compatible:
https://www.freepascal.org/
https://www.lazarus-ide.org/