You're asking for people to be convinced to play in open. That is the thread title.
Yes I am a bit puzzled as well. He wants to provide an incentive for players to play in Open, and then claims this thread is aimed at players who always play in open, it's a puzzle indeed. If they always play in open then they don't need an incentive to play in open, they already do. So the target of the post in theory is people who play in solo and private groups, to provide an incentive to get them to play in open, but when someone comes on and explains why they pay in solo he dismisses their point, because they don't play in open!
To the OP, to provide an incentive for solo and PG players to play in open you need to target the reasons why the play in solo and pg, but it appears you don't actually really care about getting them to play in open, all you want is a bonus for playing in open, I think that about sums up the contents of your posts.