A combination of huge pressure from certain clubs and the looming independent investigative body that was threatening the PL. It was a statement to say they could deal with matters themselves, the timing being the most fucking obvious admittance of that.
I'm pleased to see the growing discussion around P&L rules and how it only benefits certain clubs. At the moment there's still the generalisation that City just ignored the rules and now teams can't, but the more traction behind that conversation the more likely we'll get someone to repeat what Martin Samuel said many moons ago regarding the FFP rules and what the true agenda behind it was.
Fair on the 'show of force' in the face of an independent body. Don't think 'pressure from other clubs' would have really played a part into them throwing any old shit at it with that putting themselves into the position you described. But that's only on an assumption that nobody can possibly be that stupid.