It seems to me the main issue is brakes. Exactly why, I don't know. Wet brakes and wet clutches have been around as long as I've been working on tractors (long darn time). Case, IH, AC, Ford, Cat, Deere, all had them. Every one of them pushed their oil as the best product for their tractors. Okay, I get that.
In this particular case with the 6200 the thing that burns me up is the dealer shop spokesperson insisting the brake failure was caused by non Hy Gard fluid being used. I put brakes in a 5065E just this past summer. The brake lining had come totally unglued. Large flakes of it were everywhere. That tractor has had nothing but Hy Gard in it since day one. That didn't make a nickels worth of difference. Brakes wear out like anything else. Yes, the right TYPE, WEIGHT, and GRADE of oil, the condition and cleanliness, all do indeed make a difference. But not necessarily the brand on the jug.