Do tubes matter beyond gain stage on preamp?

“Everything matters”

True that! 

"Tube dealers confide that tubes beyond gain stage dont meaningfully impact sound, saying its what people want so its done."

Please post details of the "tube dealers" who told you this.

+1 @dekay

Which tube dealers told you that? They're either manipulating you for some reason, or they don't really know what they're doing.

A list of who said something that incompetent would be a service to all of us.

Waiting to hear.

All these comments indicating "everything matters" are correct but they are missing the essence of the OP's question I believe.  He wants to know why many of the higher end preamp designs only use a pair of gain stage 6922's for instance while a manufacturer like Cary or Manley will use an all-tube design with pairs of input, driver, and output tubes combined into the design. I think it's an interesting question and suspect their are schools of design in play here as well as cost of components.  

Short answer: it's not a yes/no answer, they do vs. they don't, it's a question of percentages.

Long answer: it's impossible to generalize.  Almost every tube preamp is going to have a different design/topology.  Depending on a number of variable factors, you can make a preamp that uses just two tubes + ss that sounds better than one using eight or twelve, and vice versa is also true.

As 3-e-p says, beyond this you're getting into design philosophies that different designers hold up as being the best (or which suits them best).