I thought textbooks were made with hardbound covers.
Some are but not all. Especially in Lit courses the schools are just buying the same paperback you and I could get at Barnes & Noble. Sometimes the paper is so cheap that it’s little better than newsprint.
For the other courses they still use hardbound books but the bindings are getting cheaper and cheaper. The “hard” binding is glossy paper laminated over cardboard. The cardboard gets cheaper and flimsier as the years go by...