I understand your frustration - I really do. I can't think of any comparably supported club who have enjoyed so little time in the top flight in the past 40 years (if you're nearly 60, at least you were old enough to really enjoy the John Harris years). So I can't argue against your wider point regarding stewardship of the club over much of that period.
But complaining alone does not take us forward. There is surely a responsibility to propose workable solutions, beyond simply, "spend more money" or "show more ambition." Whatever you may think about McCabe, he did spend an awful lot of money (he says £80m-£90m). If amount spent = ambition shown, he and therefore the club showed ambition. It didn't work! Just as it didn't work for countless others who have blown tens of millions chasing the dream (I accept we're the only one of those, currently, stuck in Div 3).
The new owners have spent money and pledged to spend more, within the limits of FFP. I see absolutely no reason for the current owners to buy into a club in Div 3 unless they believe they can win promotion to the Premier League within 5 years, as stated by the Prince. Without a Premier League 'asset' they will never recover their investment.
"Some of the people running the club past and present have no shame and no fucking heart....." I agree with your "past" assessment - pre-McCabe; McCabe, despite his failures, cares deeply about Sheffield United and it's too early to judge the new owners as heartless and shameless.
Whilst I don't always like to read or hear what I perceive to be unfounded negativity about my team, I do accept it is important for owners to be regularly held to account, so I have no problem with your stance. But I would like to hear more about your solutions.