When talking about front end for big Enterprise web apps you might be right but the proper use case for something like bootstrap studio etc, is mainly for small websites and applications that don't have any specific needs other than the basics, and to say that one isn't supposed to take advantage of modern automation software just because they don't have a profound understanding of the internals, is like saying that software developers should code in C or even COBOL, instead of modern scripting languages like python, php, c# etc, P.s. as far as semantic markup goes, I've seen some pretty clean code generated by bootstrap studio, and I'm sure there are other tools who do a good job of generating clean markup.