This has been my experience as well. I went to a small liberal arts college for undergrad. My teachers there did very little research, but all taught their small classes by themselves with no TA.

My particular field (music) tends to be much more expensive per student since private lessons must be taught one-on-one. One physics professor could teach 15 students for three hours a week, but a piano professor needs essentially needs 15 hours to teach each of those students for one hour a week. Some of this work can be done in small groups/classes, but higher music education is much more individual.

Some of my colleagues who have graduated now teach at liberal arts schools where their tenure requirement is essentially one presentation at a regional conference or one publication, with a strong record of teaching. Compare this to a large institution, where the expectation has traditionally been that you need a book deal in order to obtain tenure, whether or not you're much good as a teacher of undergraduates.