The 50mil figure is vastly over blown anyway, 30million of that is for getting to around the quarter finals anyway, Arsenal/Chelsea/Utd generally speaking get 25-35mil every year anyway because they almost always get to the later stages of the competition, winning it is only worth 15-20mil more than they usually get every year.
So if you made a 70mil loss, which they did, then the extra 15mil isn't going to make a dent in that. Don't forget there will be MASSIVE bonuses for any team winning something, winning a double will likely increase the bonus over winning any individual competition. Meaning 15mil extra they will get from winning, I'd guess at least half of that will end up going on bonuses.
Winning comes from being in the champs league, 2 poor teams in almost every group every year, 20-25mil for getting to the first or second knockout stage which basically any english club can do 9 out of 10 seasons.
Chelsea didn't make a whole hell of a lot extra by winning. Most if not all the CL regulars have a wage structure/squad size that already takes into account that pretty much certain 20mil, most teams who can be somewhat certain of reaching later stages will spend more on wages and a bigger team, that money is already being spent basically. A winning run which gives you 50mil, is only worth 10-15mil extra for top teams, where as missing the CL means the team will run into a 30mil loss compared to normal.
I know teams who aren't certain to be in the champs league are more likely to have wage increase/reduction based on being in/out of the cl, but the top teams, not so sure.
The additional income more than likely comes from sponsorship deals, merchandise and all that other stuff. Big Ron Gourlay told the press that winning the Champions League would provide Chelsea with an additional £100m in revenue.