The Tour purses have increased for decades. Players get to play on premium venues, they get courtesy vehicles when there, they get aid with accomoodation while there. They get treated like champs.   If you want to debate that maybe purses need to increase, then sure. 

But it is the same argument the WNBA is making.  The money sponsors will pay is what they will pay.  And they can go to Europe or Saudi Arabia or wherever if they want more, but lose out on playing in the other league as a result.