Yes, it's hard to stay that bad for that long.
Flyers are not systematically incompetent, their drafting has probably been middle of the road, maybe better than average after the 2nd round, player development is middle of the road, pro scouting worse than average. Just enough to stay mediocre, which they've been the past decade, 4 PO appearance, 2013-14, 2015-16, 2017-18, 2019-20.
The key issue has been lack of a coherent strategic vision, Holmgren traded Carter/Richards, then instead of rebuilding, patched for 2 seasons, then Hextall started to rebuild, stopped for 3 years, then made the B Schenn trade, Fletcher was hired to "win now" which worked for a year then failed due to lack of talent and bad luck (Patrick, Ellis).
What stands out more than anything is this lack of consistency, stumbling from one GM and one HC to another, no long-term focus, no vision of what the team should look like 3-5 years down the road.
You can run a successful tank (with a little luck), you can rebuild without tanking by focusing on incrementally improving your talent base.
Either way, you have to determine your strategy and then implement it.