It seems to me that a big part of the difference in some fields at least is a desire to build relatively solo vs in a group. In the social sciences/humanities

It seems to me that a big part of the difference in some fields at least is a desire to build relatively solo vs in a group. In the social sciences/humanities researchers don't have to deal with any other people very often; in the lab sciences there's a very small organization to work with. And 2/3 of the things all academics hate the most are the things that involve having to work closely with others and bureaucratic organizations (faculty meetings/service and grant writing. The third, incidentally, is grading.) I get the sense that the work of almost all founders involves having to get stuff from other people lots more pervasively, from funding to hiring to organization building. (Different attitudes to risk might also be a part of the difference.)