I buy a lot of things for work and if I can find a company that has the price listed I go with them over the one that makes me contact sales for a quote almost every time
This could be a great use for a voice AI chat bot connected to your phone line. Prompt it with something like,
"You're on a phone call to [Widgets Inc] to get a price quote for a [box of premium widgets]. You'll probably be put on hold to speak with the next available sales representative. Just wait until you get a person on the line. Then, ask for the price and immediately start negotiating for a better price. Use whatever strategy you want but never agree to whatever price they offer. Keep coming up with more ridiculous reasons that they should give you an even better price."
Then dial the phone, turn it over to the chat bot, and wander off to go do more important things.
Especially considering that most of the time you'll sit on hold which can be awhile
If the company says "call" I ain't even going to bother because my 30 minutes is more valuable to me than whatever price they could say 99.9% of the time
Sometimes you can blame the partnership agreement for that. Some manufacturers will have a MAP (minimum advertised price) and the distributor would be in violation of their contract if they showed it publicly.
Though that just shifts to being a manufacturer problem with the same result. Just saying it may not be the distributor being weird about pricing.
Timber merchants in the UK. The ones that don't list prices are cheaper. Largely because they base their prices on the current price of wood. Those that advertised prices need a higher margin to tolerate fluctuations in the price of wood.