I saw the Flyers play recently for the first time this season, and they looked pretty good against one of the league’s best teams even though they had a bunch of guys out of the lineup. This made me wonder, what went so wrong so fast to take them from being a Stanley Cup contender in 2020 with a nice mix of youth and experience that should have kept them near the top, to missing the playoffs last year and winning only 30% of their games so far this season? I don’t see any reason for it, but I don’t follow them very closely, so I’m asking you Flyer fans, please help me understand what happened to your team.

I feel like a lot of that "Stanley Cup contender in 2020" stuff was mainly a fluke. They did very well that season, but it was really just because they got hot at the right time. Sometimes mediocre teams just get hot and start killing it (look at the Flames this year).
Main Reasons for Failure:
1. They just aren't a great team. Not really any major superstars or insane depth
2. Injuries have plagued them
3. The top 8 in the east are too strong. The playoffs were pretty much determined from the beginning of the year
4. They gave up midway through the season. They're not as bad as standings suggest because they accepted the tanking awhile back