Well, I will say all this speculation sure makes me feel that if players can switch sponsors so easily, then I guess it is their own talents, and not certain discs, that make them play so well in the first place.

Of course, don't we all already know that?
Which is, of course, contrary to how advertising and selling discs goes in this sport. How many people buy discs from certain companies just because they have certain good players on their team? The manufacturers will always promote their them with either an explicit or implicit message of "see what he or she did with our discs! You should buy these discs and throw them too!"
But isn't this also true in nearly all other products? We Americans can be so stupid; why should I ever use a certain product just because a successful athlete is paid to tell me I should?