Glazers, Woodward, Judge(contracts), previous and current managers, the players....
The Glazers is the most fundamental problem. Replacing them, with owners that prefer winning over $$$, would cause major changes at the club. Simple as that.
Woodward: We do not know what decisions are his, the board or the managers... Can't know for sure. So thinking that he has everything or nothing to do with the problems at the club, and replacing him will either fix nothing or everything. Well, not likely.
Managers: Same issue as Woodward.
The players: Could argue that 75% of them are not good enough(their abilities are a long way off, or age has taken them) to play for a team that is fighting for CL/PL titles.