Just my thoughts...
It's very sensible and understandable to suggest that somebody go do a PPL and fly on it for pleasure, whilst earning proper money from a proper job outside of aviation. This nearly happened to me, but I'm on stab two of the flying thing now.
It doesn't quite work like that, I fear. If your wish is to FLY, and have a lot of fun doing it, then sure, do a job you enjoy (probably in business, where most of the money you earn is yours, or working for somebody using a specialist skill), then fly at the weekends, grab a share in something fun, tour Europe in it, go on flying holidays in the U.S. and the bahamas, etc etc. Yeah, it would be a lot of fun!
But this misses the point of why many people want to become, specifically, pilots of civil jets. Some people (myself included) - are very much interested in flying, but just as interested in doing a job that keeps you out of your comfort zone and out of your local patch. It's not all about the flying, it's about the strange places you are flying TO, and the unique challenges each place represents.
It's about feeling you're doing a job you genuinely enjoy getting up to do. I'm sure this wears off, but it won't wear off until you have done it. To digress - most people know what it's like to drive along a road with hundreds of other commuters, all heading to one place of work or another. It makes early mornings a bit sh*tty, truth be told.
How about driving along a road with hundreds of other commuters, but YOU are on your way to take the aforementioned 60 tonnes of aircraft at 600 mph to somewhere rather spectacular (or not, depends where you're going I suppose!).
Of course this post will read a bit cringe worthy to the experienced pilot, but it is an attempt, written in lay terms, to get at the question asked by the OP, of why people put themselves through this.
And referencing to friends of mine 'doing the job', there is a big difference between taking an SEP or MEP across the Channel bashing into short strips, and being sat at the front of an airliner monitoring computers where you're away in Cuba, the Maldives etc for a week.
Point being, they're completely different, therefore will attract different kinds of people, although that is a totally separate argument and I don't want to be around when it's discussed!