Unfortunately, very very few people make money from being able to play guitar. Obviously I'm omitting teaching in this, but that's a different story.
Being a session musician is often a very far cry from what your expectations may be. Studio work is not a glamorous job, there is a lot of waiting around for artists to arrive (talking in a 'big' studio here, with chart records), and then when you have to record, you cannot have a dozen takes at something, you have to be spot on. d there's not really any sight of tabs, you might get the names of the chords if you're lucky, and you have to know them. There are a handful of musicians who can make a living, but it's not really the musicians you need to know, it's the producers and the managers who book the work!
The music industry really isn't the place I would advise anyone to aspire to work in, there is so little reward for your efforts at the top, and no money below that. It is a shame that is the situation, but if I were you Steve, I'd be pleased with myself for figuring it out before you get into financial trouble.