I think it's fair for many to be objective in their assessments but I can't see INEOS being a success given the resources around their respective ownership model and their approaches to resolve issues essentially exposing their own limitations.
The situation with the Glazers is such a unique instance that Manchester United's demise under their occupation is so bad it reflects poorly on the premier league for having such a poor sustainability criteria that newer rules to 'protect' clubs only happened after the Americans intervention.
Subsequently, that's only looking at the facilitated debt and omission of infrastructure development but then when you observe Woodwards / Murtough's ineptitude, it further compounds that issue with the money owed to clubs and the crippling finances which is the concurrent circumstance of the clubs efficiency today.
All in all it has created this extraordinary situation and provisionally the only ownership model that would resemble rectifying everything with the least amount of friction from an operational standpoint is middle eastern ownership or a very nuanced consortium.
INEOS simply don't have the resources to resolve these issues. The analogy that comes to mind is someone who earns 7 figures a year but is shopping around for a Koenigsegg. That salary despite being economically high is still not conducive to the market in obtaining that car assessing cost and expenses. The situation the Glazers have created has put United into a very exclusive market that the average owner can't rectify.
The current ownership is a bit of a muddle. And unorthodox, in the sense that a minority shareholder has more sway than a typical minority shareholder. The general consensus is that either INEOS becomes a majority shareholder or there is a full sale. As I mentioned before, a full sale might not mean a club without some Glazer involvement post sale.
I don't agree about resources. All of JRs failed bids for the club had him buying out the Glazers. The last rejected bid would have him paying slightly in excess of $33 a share for all the B shares owned by the Glazers, and that deal, had it been successful, would have required around $3b more funding than the existing deal. And Proof of Funding would have been provided at the time.
In may ways, what a wealthy owner can do in terms of direct investment in the club is restricted by FPP and PSR if the club is borderline wrt to the tests.
Direct investment in one or more of Women's football, community, and youth development (friendly expenses) will not improve a Club's PSR, or FPP position. Sure, the extra costs can be deducted from running expenses (wages and other operating expenses) but such investment is not revenue generative in the short to medium term. Hence, no impact on PSR.
Direct investment in facilities and the training ground (like the Carrington investment) does not impact PSR or FPP. Fixed asset value increases leading to greater depreciation costs, but as depreciation is considered a friendly expense, that too is removed from the PSR\FPP determination. As this investment does not generate revenue in the short to medium term, there is no PSR\FPP gain for the next few monitoring cycles.
Player trading is a bit more complicated. Can an owner invest heavily in new players in a situation where the the club is operating (and projected to be) near the testing limits? They can, but only if the net trading cost is close to zero. Signing a bunch of new players bring new costs (amortization and wages), but offloading unrequired players reduces those same costs, and there is the opportunity for profit on player sales. If profit on player sales is roughly equivalent to the net increase in costs, then PSR\FPP isn't in peril. Of course, if the investment in the squad is successful, then it should show in revenue (eventually), but the expectation (given our experience) that it would happen immediately is not prudent.
As for cash flow, to the extent that the owners provides direct funding to meet those costs, then cash availability is not affected.
Direct investment by an owner for a new stadium would improve FPP\PSR once the stadium is in use. Revenues increase and the enormous depreciation charge is ignored in the testing. Cash availability improves as more earnings pour through from operations.
Paying down long term debt would improve both FPP\PSR and cash flow as finance costs impact both.
Putting funding in place to cover the football debt (a problem at United) wouldn't change FPP\PSR but it would greatly improve cash flow as future earnings would no longer be required to deal with those obligations.
Those last three items would require pretty substantial direct investment from the owners. Now, the club does have an ongoing registration with the SEC to raise up to $400m from the sale of A shares\debt stock that can be exercised at any point. The registration has been amended to account for the INEOS buy-in. Whatever about the ownership machinations, you can at least assume that both parties agree that this facility could be useful.