Yes, but he CANT solo all the time, that's practically impossible, also if he draws when he is like at 1000 pts. GR then he will lose a shitload of points, which takes a hell lot of game to get back.
At 1000 pts. GR, you can earn 600*2/35= 34 GR pts., but with a single 3-way draw you lose 27

. At 2000 pts. GR you have to solo 2 out of 3 games to stay stable.
Eventually it will plateau.
A solution could be, the bigger the GR spread in a game is, the smaller the stake gets.
So if the game's GR average is 150, but there are 100pts. and 400pts. GR players in that game, than the stake should be lower, as there were players only from 120-180 pts. Basically this would punish you if you play out of your league (both way)