From what you relate of that Dealer's comments, beliefs, and "spiel",,,,,
Pick another Dealer/Installer ThumbUp
Never been a Fan of or trusted a "One-Trick Pony" to be completely knowledgeable or sincere. As I've said before, those either sell you on the only thing they have and do or they don't get your money. Their Goal is to get your Business and your Money. As such, they are going to be true to THEIR Mission & Goal and say whatever it takes to accomplish that.
Conversely, a Dealer that has several choices and Offerings can sincerely present many Options and still accomplish their Goal and get your Business. Much rather go where I have an A, B, C, or even D choice rather than a Yes or No. Better situation and opportunity to make a correct remorse-free decision as well as to receive complete, accurate, and honest information for the Buyer.
Also, how does someone who only has and knows One Product or Thing REALLY know about the Rest to even be able to credibly talk about the Rest from an intelligent and informed position?
Don't buy my Shoes from the Dude that only sells Reebok (unless I have done diligent and complete research on ALL and concluded Reebok was right for me and what I wanted and needed). Definitely not gonna buy what he has to say about Nike, Merrell, New Balance, or the rest.
*nothing against Reebok (just threw the Names out at random to represent the Point) or Champion for that matter. However,,,, like to explore ALL Options before making my own Informed and Intelligent Buying decision. Can't do that at a One-or-Done/Yes or No Location.
Good Luck and all the best in whatever you do and decide ThumbUp