Some interesting points there, mate, but I have to disagree that their decline is conceivably terminal. I get the Adam Gimbel analogy, but it's right to say that his eponymously named department store was trading successfully for many decades after Macey's opened, albeit under more restricted circumstances. I think I can say with some confidence that the likelihood of them returning to the dominant position they held a decade ago is so remote as to be nigh on impossible, but that doesn't mean they won't continue to feature around the top of English football going forward. It may require a sale by the Glazers to ensure that outcome, and for much less profit than they had hitherto anticipated, but something will have to give eventually - and when it does the 'brand' has too much residual value and recognition for them to sink into mediocrity, much as it pains me to say it.
How soon can the Glazers afford to sell, though? More pertinently, to whom? Manchester and English football generally has very probably been ring-fenced off from Middle-Eastern and Chinese investment now. So what's left? Glazers MKII? Venky's MKII? Thaksin MKII?
Any of the above are just as likely as a new James Gibson (of whatever nationality) on a white steed. I get what you're saying about the residual value of their brand but you know, it's from monetising such entities that the likes of Mike Ashley became mega-rich. If Utd were to falter as a cash cow, the Glazers will sell to the highest bidder. Utd would need to be very fortunate for that bidder to also be the most suitable candidate. They'd need to get luckier again after that on the football side of things. And need to hit the jackpot to be able to sustain such successes.
Their name gives them more hope than most - just as ours did when we were down amongst the dead men (or Leeds does now) but it requires a bit more than a famous name to even beat Bournemouth and Norwich, let alone anything else. It's quite likely that they'd do a Liverpool but it's equally possible that they go into a nosedive. A good brand is all very well but I'm not at all sure that it's the guaranteed safety net they think it is.