That's me. I switched 3 years ago because I saw exactly this. I originally did it to gain more tech skills with the plan on going back into it, but I left and didn't go back. I took a bootcamp, and about 1/3 of my class were ex-wall street.
Finance is a huge industry. I can't really speak to the average, but I was a buy side equities trader.
Technical: All of us are well versed in excel and have working knowledge of SQL. Going from VBA to ruby/javascript was pretty trivial. While I don't really consider college all that meaningful, most people had been STEM majors, so the non job-specific knowledge tends to have some overlap. I was a math/econ double major with a stats minor. Had I dropped 2 econ courses and taken data structures + computer architecture, I would have had a minor in CS. The rest of the minor overlapped with my math/stats.
Work-life: Finance is a very hard-working industry and had a ton of continuing education, so that transition was extremely easy to the tech life. I previously worked 60-80 hours a week (dependent on earnings season) and went from that to 50 hours. All that free time went towards a few hours of extra sleep and MOOC work to catch up on some of the more fundamental CS concepts.
the current generation being hired into wall street (people around my age) have some kind of engineering, mathematics, physics, CS background in huge amounts. finance hires people like these by the boatload into all kinds of positions: risk, research, trading, sales. software development permeates the entire value chain in the industry.
