First we have no hint that developpers consider the economy hyperinflated or not
I've also said this before, I believe they want inflation, and more of it.
How much of the total salary mass would be need to be raised to compensate this ?
Well, they said they said they were going to raise salaries last season in such a way as to be almost a neutral effect, yet in fact their proposed salary increase actually caused salaries to fall slightly. For Foto's reference, this is from their news post. This season they're saying salaries will raise. However, they've chosen to increase salaries but making it even more difficult to do anything other than play LI, something users have been fighting against for many seasons, and not by raising salaries across the board.
Salaries would be the easiest way to curb inflation, if the BBs wished to do so. As I said I think they don't. I think its clear that the majority of users do not enjoy the game as much as they used to, and one of the main reasons, (I have actually been told this on many occasions) is the economy. Some people actually already regard it as broken.
This next part is conjecture, but I do think they BBs are trying to inflate the economy because they think this will make people train. I think this is flawed, I think it won't work, and it will continue to piss people off.
They don't tell us anything tangible but they do often drop hints, and I think its clear they'd like to see more of training more players. They could help us do that, but they've decided instead to try to force us.
I'm sure the staff will be along now, those aren't so petty as to ignore my posts, to tell me that if we don't train there won't be any players and is that what I want. To avoid that I'm going to say now, no, I'd love for everyone to be able to train.