[ftyers]

That's because they like doing research, not because if they don't do it they'll get fired. If they wanted they could just take that time off, they have tenure after all. No classes basically means no work outside of the work that you want to do.

[kaitai]

Do you understand what it takes to get tenure in the US? Generally 10 years post PhD of grinding, working summers and weekends. (That's from 3 years of postdocs and 7 before tenure.) By the time you get tenure you don't know how to not work through the summer, and you have graduate students who need to be supervised (they'll be doing a substantial portion of their research over the summer and you need them to get through). You'll have grant funding for summer research (because if you don't, you didn't get tenure) and you'll need to ensure that the work you've promised to the granting agency gets done in some form or another, not least so that you can get the renewal or extension of the grant, which is needed to pay the graduate students. You'll have some conferences that will require travel, and you'll need to get things done with your collaborator before she goes on sabbatical and your other collaborator before he becomes dean of students. You'll have a revise and resubmit or three, and you'll be trying to finish another article before the August 1 submission deadline for the special journal edition (yes it'll be pushed back but if you let it slide, the grad student working on it will start teaching mid-August and then progress will slow to a crawl and you'll really run into trouble, that student is supposed to be transitioning to another project as well due to a grant you have starting at the beginning of the academic year).

Heck, I have been out of academia 4 years now and I still have minor revisions to a paper complete in the next week!

[ftyers]

I'm 5th year TT at an R1.