Looking at the math of buying a PSL on the second hand market and reselling:
400 section are going for $7000 for a pair of PSLs and all 10 games for 2021, which cost $89 each.
Stubhub has them listed (same section, similar row) for $170 a piece for the Eagles opener and $120 for the Panthers game (lower attendance). Let's just give them a weighted average of around $160.
Costs: $7000
Gains: $3200 gross ($160 x 10 games x 2 tickets)
Total gain after Stubhub fees: $2784
Loss of $4216 for the first year. Assuming the PSL is paid off in 2022 and the pricing stays the same, you stand to gain roughly $1k per season if you only resell the tickets, making the break even cost somewhere around 5 years, assuming that you are able to sell every ticket to every game. You also get to sell the PSL at some point, so it retains its value, even if you sell it for pennies on the dollar, you are still paying for it through the sales of your tickets.
My overall conclusion is that it is possible to make money or at least have it pay for itself in the long run, but there are certainly risks involved. I'd rather invest in a better asset.