Uh, first off, the airlines (and thus the passengers) are the ones paying the cost. Not only the cost to design and certify, but also the cost to train flight crew and mechanics in a new type.

Secondly yeah, the manufacturers do actually ask the airlines what they need. They are not building hundreds of thousands or millions of planes like auto manufactuerers build cars. They are, at best, building a few thousand aircraft. The manufacturers build what the airlines want, and airlines don't want expensive jets that come with a lot higher costs.