I'm impressed by the certainty you have that the only possible future under Hall and Shepherd was financial ruin.
Hall and Shepherd were spending beyond our means chasing the moon, but that doesn't mean a) they would continue, b) Ashley was the only possible new owner around or, c) neglecting the club is better.
We can go in circles for decades if you want, but Ashley has clearly no ambition for Newcastle beyond surviving in the Premier League on as modest a budget as possible (see this transfer window for proof). He's turned us into the turd that won't flush (except for the 2 times it did). You might think that's aspirational for us, but when clubs like Leicester, Brighton, Leeds, Wolves, West Ham, have all shown more ambition than Newcastle, it proves that it's not reckless to want more than mere survival.
You, as a Sunderland fan, might think Newcastle United are destined to be bottom half due to petty rivalry. But the same logic that says no club deserves to stay up, says no club is bound to be bottom half, either.