I think you guys are overstimating (or overcompensating) the level of acceptance of homosexuality in football. The culture war might seem well and truly won on the surface, but away from publicity there still will be plenty of teammates, coaches, staff, fans, and even owners who are not comfortable with openly gay players for cultural (football is a global game, don't forget) and religious reasons. Once the initial media hype subsides, the player in question might find himself silently ostracized and before long pushed out from the team. If something like this happens and he chooses not to be silent about it, there will be a media firestorm which will be a huge distraction to that player's career. And conversely, if that player's agent will try to use his client's gayness as a bargaining tool (which they surely will), this can lead to all kinds of media wars and negative perseptions. Just imagine what terrible things people would say if Lallana came out as gay and later got "rewarded" with a bigger contract than Coutinho...
There is a reason no active player in any of the major leagues has come out up to this point and don't forget that the last guy who did so in England was hounded and driven to suicide - not that long ago. And people are still being persecuted or even executed for being gay even today in many countries and most of these countries do play football (and some also produce mega-rich guys who own top-4 English football teams).
The players who have decided to come out will surely receive a lot of support from all quarters, but don't underestimate the risk they are undertaking.