I would disagree. Assuming one doesn't have the £84k for the FPP, they would be taking a loan and probably paying back around £120k. BA return the £84k over your employment, so you would end up footing the bill for the interest at around £40k. A Ryanair type-rating is E30k. Add that to a modular CPL/IR and you would have to do very well to beat the FPP cost - and this is in its most expensive case where one requires a loan for the full cost of the course. Remove the need of a loan for the full amount and it becomes even more cost effective. Your option also assumes that one would get a job with Ryanair having already committed to the license cost. It isn't that easy when there are thousands queuing up for the dubious pleasure of flying for Ryanair.
Then you consider the long-term career prospects at Ryanair vs BA, the security of having an actual employment contract + benefits, the fact you have an employer who isn't actively trying to screw you over every 5 minutes and it becomes a no contest.