It’s simple
The club spends money than it earns
It’s a self sufficient model that the club has always followed
Yes but it's now a broken model
Abramovitch broke it
Humpty Dumpty UEFA tried to put it back together again with FFP
Manchester City broke the model again, swept up all the broken bits, and put them in an atom crusher just to make sure UEFA couldn't put it back together again
Hence the aborted (for-the-moment) Super League
Nobody can reasonably blame FSG (and other owners) for exploring the Super League option as Manchester City's lawyers have smashed up the business models of LFC, Manchester United, Arsenal, Spurs (and even in more recent times, Chelsea) when they took on UEFA and won. OK Super League was badly handled from a PR point of view, and had design flaws, but there is a clear rationale for exploring it.
FSG now have 3 options:
1) Sit down with Perez et al and get a better version of Super League thrashed out, one with promotion and relegation to keep the natives happy. What about play-offs? Fancy some play-offs? Imagine all that lovely TV money when Borussia Dortmund play Forest Green in the final.
2) Sit back and accept that LFC cannot compete with clubs whose owners have a bottomless pit of cash.
3) Sell the club to such an owner, who let's face it is hardly likely to be everyone's favourite cup of tea, and the UK gov may even possibly take steps to shut down this 3rd option going forward anyway.
If that leaves us with option 1, LFC fans will protest
If that leaves us with option 2, LFC fans will protest
And if option 3 isn't shut down and comes to pass, LFC fans will protest
Once FFP got put in the atom crusher, there is now no outcome for this club that won't cause large parts of the fanbase to be up in arms, possibly permanently.