It's just such a different thing though. It's not like there are "returning starters" like on an offensive line. Only Neris fits that description, and he's actually been admirably durable and consistent for all his warts (so much so that you worry he might finally implode, if only due to age).
We also just have to hope that both the scouting and the coaching is better this year. COVID was also a factor (affecting Suarez and Arano, at least). And they blundered on Seranthony. And obviously pitching coach has been an absolute disaster for this franchise, though I think last year also shows that there's only so much a pitching coach can do - Price had talented starters and did a good job, he had lousy relievers and did a bad job. But at the end of the day, he wasn't good enough, and, it seems, wasn't sufficiently engaged either.
The 2019 team wasn't a great bullpen either, but it wasn't the thing that ruined their chances compared to Cutch's injury and the rotation.
The similiarity, I think, is that the 2019's bullpen injuries - cutting across young and old, internal and free agents - were at an epic scale, as was 2020's poor performance. Nobody thinks the bullpen can just go from giving up 7 runs every nine innings to giving up 4 runs every nine innings but even if they can get to 5.50 - the mean, if you will - last year's team would have had a winning record and playoff berth (though it remains to be seen if just being over .500 gets you one this year). That's different from hoping a 9-7 Eagles roster can get back to 12 wins.