If you're not on the salary level of top lawyers or investment bankers, it's quite a big financial sacrifice once you're no longer free and single
That may be a bit of a sweeping statement. A good lawyer might be on £300k. Good fund managers on much more. You can do an awful lot of flying on that...
Flying is not a dirt cheap hobby but equally it isn't that expensive. A really high hour pilot, zooming all over Europe in a nice IFR tourer, might be spending around £20k/year. You can do a lot of VFR flying for a fraction of that.
Also, "free" is not necessarily "single". If you are a bloke who likes flying, and you shack up with a woman who hates it, who is to blame for this?? Nowadays, everybody has options when it comes to relationships. Internet dating has made it far easier than it used to be. There is no excuse for getting stuck with somebody who has a totally different agenda. The problem is that most men are mugs, and go for the first pair of t**s, get her pregnant, and moan they haven't got any freedom
