You have a fair point, and that’s that tuition is another item where customers frequently don’t even shop on price. Many students decide on school with only a vague idea of price, some are on scholarship so they don’t pay, some are not that sophisticated with money so they just ignore the price and take out expensive loans for whatever they tell them to pay.

But the main reason why the idea would help is that colleges set tuition based on what they think the market will bear. The actual cost of the books though would be the school’s problem. Administration might actually pressure professors to NOT use custom self-authored editions that cost $200 more. Also, if the books are included, the school would want to buy used ones from any students who didn’t want to keep them, since it would save the school money. So they would be incentivized to tell professors to not switch to the yearly “new edition” which just resizes a few callout boxes each chapter in order to screw up the pagination, and randomly shuffles the exercises.

* note: I’m imagining here that tuition is set to a fixed amount for everyone just as it is today, not that everyone’s tuition is computed custom for them to include the books their particular professors picked.