> The quality of curriculum and teaching was typically poor
I think this is, perhaps, to be expected. 4-year universities practice selective admissions, whereas community colleges generally let anyone enroll. Community colleges make opportunities available to all, including some who find they aren't well prepared for them.
> the equipment was only adequate.
Tuition is much cheaper than at 4-year universities. This is inevitable.
Mind you this was 10+ years ago. Maybe things have changed.
As for the textbooks, I'm curious what you observed? I'm unaware of any university profiting in this manner. I am extremely aware of textbook publishers profiteering, as well as the occasional individual professor-author who shamelessly convinces the rest of their department to adopt whatever book they wrote.
But the most likely reason that the book changed, in my estimation, is that individual faculty members are often given leeway to choose their own textbooks. This has some negative consequences, but in my opinion it's a good system overall.
And, incidentally, if you want the best deals -- then I'd recommend that you neither buy your books from the school, nor sell them back to the school.
I'm not from the USA, but UoP is notorious.
Emphasis not in original.