I've started a couple of responses to the OP but couldn't articulate - this sums much of it up. In our case (Pompey) the model was a bit different to yours, but the circumstances that landed us there were similar.Generally it is a crisis that causes a Trust to end up "holding the baby" at a football club in the first place. But in the absence of a sack of cash, a Trust-run club then needs a viable long-term strategy to work to, and a steady stream of willing and competent volunteers to pick up the reins when those who have stepped into the breach have to bow out for whatever reason.
I suspect many of the clubs who are no longer Trust-run had neither of those things, and have had to throw in the towel and sell up. It's been a tightrope-walk for City though - without the sale of Matt Grimes we probably wouldn't now be Trust-owned, or would certainly have needed some kind of external help. (We had to resort to PFA loans to pay the players wages that season). But of course it was the Academy-focused strategy adopted by the Trust that created Matt Grimes in the first place, so we kind of "made our own luck".
Our senior player recruitment does seem to be improving now, and so hopefully we won't have to rely solely on Academy graduates for transfer income. (Other than Stockley, I can't think of many signed senior players from the recent past who have earned good transfer money). But in the current squad, I'd be willing to bet that Sam Nombe has the best potential to earn us a Watkins-style windfall.
But it will continue to be a tightrope-walk, as we are running a fairly hefty operating loss funded by capital from Watkins/Ampadu/Chrisene/Storey etc so there's no room for complacency.
In our case, we got interest from a seemingly creditable outside investor showing interest within a pretty short space of time - so for many of our supporter-base it didn't seem like a throwing in of a towel, more an option to accelerate progress with relatively low levels of risk. Had that not been the case I expect we would have had to evolve our model and governance.
I'd have liked us to have continued down the route we were going; but also accepted that those investing in us seemed like relatively reputable custodians; and offered a degree of security that we didn't necessarily have under the previous model.
One of the reasons I keep an eye on here - and on City in general - is that I love what your Club does and how it does it. I can see it has it's own imperfections and challenges, but as a Trust and fanbase you've created something brilliant. I'll stick with that if you take six points off us next season.