All 4 are finished at top level, certainly. Some due to brutal beatings, some (Fury) mostly due to lifestyle. All have many miles on their boxing clock. Anyway, which pair do you consider more spent and less relevant in the division
Probably Joshua and Fury. With Tszyu I'm not entirely convinced he's done at the top level. He's past his peak yes, but in all fairness I'm not sure he could've ever beaten Muratzaliev and the Fundora of the second fight, even during his peak. With a few more confidence building comeback opponents I could see him mixing it up with the 154 top 10 again and winning a title at 160. Never gonna beat the likes of Boots and Ortiz but honestly was he ever? As for Spence we'll see how much he's declined later. Fury and Joshua on the other hand are both conclusively old, worn out and past it. Fury's legs have slowed and is fat. Joshua's chin is gone. No amount of confidence builders can get them back to the world level at this stage I reckon.
As a pair, I think fury and Joshua are more shot. The main reason for that is that I don’t think that Tszyu Is actually shot. I just think he was overrated to begin with and while he may be a little worse than he was a couple years ago he really hasn’t dropped off that much