Covenants can be broken. There is almost always a legal way of doing it. I don't pretend to know the technicalities, but a good solicitor certainly would. So I am by no means reassured by the alleged covenant on Gigg Lane.
It's a bit like "listed buildings". Some people think if a building is "listed" it is safe. Not necessarily.
Think about it. Nothing happens for five years, Gigg Lane gets overgrown, "travellers" camp on the car park and set fire to stuff, the whole place becomes an eyesore. What will the local community say then? I can tell you, they'll be raising hell.
The only way to save it is to secure it for a practical use (for example for a new football club) and to do that someone is going to have to stump up millions.
Unfortunately, this is spot on. They're not helped by the fact that it's probably a fairly attractive site for residential development given that it's within walking distance of the town centre, is a reasonable neighbourhood, has relatively decent road and public transport links to Manchester, and has easy access to the countryside. Based on what's been reported in the media, this would look like a fairly straightforward repossession of a mortgaged asset from an insolvent debtor. You'd then expect a sale to follow, and there'll definitely be interested developers.
Even if Gigg Lane is listed as an asset of community value, that only confers a right to match other bids for the land - and if a phoenix club is starting again four or, perhaps more likely, even six levels down the pyramid, they're unlikely to have the financial clout to equal a developer's offer. Developers then typically play the long game and, as you say, the oldest trick in the book if you can't get planning permission for a site is to cynically run the existing property down until everyone's desperate to get rid of it. In such cases, it's quite uncommon for the developer not to prevail eventually, whatever restrictions on development exist in theory.
I reckon that a phoenix club will be formed and, while there'll be a lot of hard work ahead, they'll probably get sufficient crowds (and thus generate enough cash) to climb up the pyramid fairly quickly - at least to National League North level. But they'll most likely start off ground-sharing outside their own town - perhaps initially at Salford City, which has about the closest decent appropriately sized stadium to them and is a club where you'd expect a couple of the co-owners in Gary and Phil Neville to be sympathetic to the Bury plight.
They're probably then going to face a long and difficult battle to get back to Bury. AFC Wimbledon have been playing five miles away from their traditional home for 17 years since their formation and are due to begin work on a new stadium in their borough of origin only next month. AFC Bury (or whatever they call themselves) might also find themselves based outside the town for quite a while, especially if, unlike AFC Wimbledon, they get stuck in non-league for a lengthy period.