In the late 1970s Peter Swales embarked on a period of very high, debt financed spending in an aim to make City the most glamorous and successful club in the land. The policy took time before it proved to be disastrous on the pitch and catastrophic off it. By the time we saw the full effects of the approach City were in the third tier and was surviving courtesy of the banks. Later we saw Leeds follow a similar approach to try and replace Manchester United as the country's leading club with possibly even more disastrous consequences. Loans were not guaranteed by an owner but secured on club assets. Nevertheless Leeds were dumped into the third tier and broke. There were no FFP or P&S regulations in place to stop either club's "kamikaze spending". The question is actually whether the regulations would have stopped either club's trolly dash and there is some doubt. Another point to make is that neither club went bust, both are still in business and in City's case .... Both appear to have been kept going by the normal mechanisms of the market. It is hard to see that the situation of either club would have been helped by a ten point deduction, or even more by repeated points deductions.
Many on here will reply that both City and Leeds relied on loans, on the great villain DEBT to finance their recklessness and this is true. And in the 1980s &1990s some clubs got into considerable trouble by taking out loans to finance ground improvements, most often new stands. Chelsea and Wolves were two that I remember and both suffered from it, Wolves spectacularly so, almost dropping out of the league. These are, however, projects requiring large capital investment and loans/debt has always been the obvious way to raise capital. Indeed FFP allows it subject to the proviso that the club can pay the interest on the loans. This is certainly not a ridiculous regulation but it is nullified to some extent by the proviso that this must be paid out of "normal" revenue, which excludes anything owners/shareholders might want to put in. Even before FFP was introduced a number of clubs built impressive new grounds and since their introduction Spurs have built a very impressive one. new stadia were certainly needed when the disgraceful standard of some was considered but whether FFP has made it easier or harder to finance is the question.
I think I want to put forward several points arising out of what I've written. The first is that FFP does not ban investment but it does limit it. It certainly doesn't ban debt but it insists that the interest must be paid out of "normal" revenue but limits the owner's ability to pay the interest severely. Many clubs find that their scope for improvement is severely constrained while others who thrived before the introduction of the regulations are left to spend, spend, spend and pile on the debt in the manner of Swales and Leeds! IF (and a big if) FFP had a noble aim I suspect it was to force clubs into good business practice. It hasn't done this. It has allowed clubs at the top when the regulations were introduced to spend and borrow more while the others find that however good their business model or however rich their owners their scope for improvement is limited. I can't think why UEFA and the PL have introduced such restrictive, protectionist regulations.