The reason isn't tenure. The reason is that research universities value research much more highly than teaching. This is evident in faculty hiring practices, ev

The reason isn't tenure. The reason is that research universities value research much more highly than teaching. This is evident in faculty hiring practices, even the hiring of junior professors who don't yet have tenure. And this is also why underpaid graduate students and non-tenure-track postdocs are doing a lot of the teaching work at universities.