A slow fade into obscurity? We are something like the 4th richest club in the world and remain one of the biggest clubs in the world. The PL recently got one of the biggest ever TV deals.
We remain attractive for now, but we're talking 10-15 years into the future here. If you look at football as an entertainment product and clubs as competing amongst each other for fans, City went from basically 0 --> 80m fans world wide in the past 6-7 years. PSG playing in a useless league grew to 40m supporters. I can't find clear data here but I'm pretty sure (atleast anecdotally speaking) that we've underperformed the overall top football clubs in terms of fan growth, so the threat of slowly losing fans and losing money as a result is very real. You can scoff at this vision of football but that's how clubs make money these days.
I think more than the PL money, the CL money is what matters for all english clubs. We're at a point where one expensive mistake can result in a death spiral e.g., we buy Haaland -> he flops -> we don't get CL -> Have to pay Haaland so we can't sign more players -> No CL etc. That's our hopes down the drain for 3-4 years at the very least. Oil clubs just don't have the same issues. Make a mistake? Big deal, throw some money at the problem and it'll go away.
The deck is stacked against us and sure through some good management we might still be fine but it's also entirely possible we end up w 30yrs of nothing like Pool have or in the 9th place in the table like Arsenal are right now and to me the latter scenario looks more likely. If not now, in 5-10 years after Newcastle are taken over by the Saudis.
Everyone recognises that UEFA and FIFA are terrible corrupt organisations. Everyone recognises how bad oil clubs are. But most people recognise that the ESL was one of the most ridiculous "solutions" which if anything, would have made things far far worse.
IMO The ESL was mostly about clubs recognizing that they can't prevent big money in football and trying to preserve their place, or atleast excluding the nouveau riche, from the elite circle. As a side effect they've excluded inspirational success stories like Leicester / WHU which is a terrible thing. I think if they had control of the narrative a bit and also had some open discussions instead of doing it all behind closed doors like a bunch of super villains, they'd have had more success.
Apart from the lack of promotion / relegation I don't think the ESL wasn't a bad idea. A European cup competition with the best European teams playing in it? I think everyone (fans, clubs, sponsors, broadcasters) would've been happy with that. The current CL + EL format is an abomination.