> I don't want to talk to salespeople, only product designers, developers, executives, and support staff. They are the people who make the stuff and/or are left holding the bag for the product when the salesperson is jetting off to their next meeting.

Lots of people overestimate their value in the process, including buyers. You don't want to talk with sales people, but from the other side, why should the sellers (in any function) talk with you?

I've purchased products. And sold them. Lot of waste from both sides, primarily when people aren't prepared, don't understand their problems, misunderstand use-cases, don't know product, etc. The list of grievances is long.