The vast majority of quality firearms are only sold used for one very good reason: They are no longer being produced.
You limit yourself to probably 1% of all firearms designs that have been made in the last 100 years if you limit yourself to new.
You, in fact, limit yourself to "one hundred and fifty versions of the same six things" (more or less) if you insist on new. How many polymer frame/steel slide trigger-cocking pistols can you be *really* be interested in? Go handle a Colt Python and a Smith & Wesson Model 25-2, and then a High Standard Victor and a S&W Model 41, and a pre-war Model 70 and a Winchester Model 52 and then come back and talk to us. Shoot a Remington Model 11 and a Winchester 97 if you like shotguns. If you find any of them new, let us know.