I think, because most people who are actually relying on Adobe products (e.g. making money with them) are making way more than it costs (by several orders of magnitude) so they let themselves get slowly boiled because they still make money hand over fist.

Everytime there is a price increase, the discussion becomes: do we retrain x people, costing us y per person and reducing productivity for z months, or do we just take the L and pay a flat percent increase per seat and maintain productivity. The choice is almost always the second one because it's hard to predict how prices will increase in the future and the costs of retraining your staff.

The people not making money have no resources to stand up to Adobe, so they make noise because it's all they can do. Adobe ignores them because they don't generate a significant portion of their revenue.

If you are an employee for a company using Adobe products, it's likely you don't even care and you may not even be aware of the pricing scheme your company is following.