As a person with a music degree, albeit not in composition, but I had several friends who were composition majors, my impression is that composers often do writ

As a person with a music degree, albeit not in composition, but I had several friends who were composition majors, my impression is that composers often do write music in old baroque or classical styles etc., which are academically well understood, but they do it more as an exercise. Probably some composers even do compose exclusively in those styles. But the point is we don't know it because there isn't much interest from general audiences in anachronistic music and of course there isn't much commercial interest either. Bach of course produced a lot of music that came down to us, but he was paid to do it as a court and church composer. He had to have something new ready to play every day in the styles that were popular at the time. That was his job. And he improvised much of it and then wrote it down and developed it later, which was very common at the time (and even now).