You might be surprised to find out how many average players only throw one brand - for whatever reason. I know I've seen several posts of folks saying they don't throw brand X or brand Y sucks, etc.
I don't know that it ruins disc golf, but it certainly doesn't give you your best chance for success if you exclude discs that might be better for you just because of the company.
I also believe that you're affected more by the pro players than you might think. The pros drive the rules we play by, the drive the development of new discs (especially faster, more overstable), new courses (as you said), sales (discs, dvds, merchandise - as sales go up, more stores are able to stay in business). Probably more, but that's all I can think of off the top of my head.
I wish I could say education - as in pros make videos and educational material, but man, that is few and far between. I firmly believe the AMs drive that more than anybody. Not that the pros don't have good advice or skill, but it sure does appear that most of them fall into the "I can do it, but I can't teach it" category.
From the few conversations I've had with Dave, I get the feeling that he's in it for Disc Golf (and hopefully a profit!) while the other companies certainly appear to be in it for a buck. Nothing wrong with that, but using an NFL analogy - he'd be a player's owner
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