I imported 10nl hands into pt3 today and I am getting the following results.
Comparatively 10nl players pay a lot less in rake than 0.50Nl players. The ratio between what people win and pay in rake is 5:1 @10nl and 1:1 @0.50nl.
I would assume this trend is even higher on high stakes to the effect that rake is negligent.
10 NL could certainly affort to pay for WPA without much problems. Though very few losers would become winners thru it.
Interestingly there are still many players that would be affected by the change in win rate with WPA as you can see in the scatter below even on 10nl. You can see winrates shifting from left to right.
The results below are filtered for players with ptbb -10 to 10 range. The winrate is displayed as $ won per hand.