The Liberty weren't a founding member, they were one of the first 2 expansion teams
Also the passing inflation isn't a sim inflation, but a correction from the very low passing seasons right before. You use S23 as an example, and S22 and S21 also are similar where the leaders had 1191 and 1281 yards respectively (in 13 games). In S20 the league leader had 1447 yards in 13 games, which in a 16 game season is a pace of 1781. It was pretty common for receivers to have 1400 or more yards in 13 or 14 games in the first 20 seasons of the league. Fyodorovich in S12 had 1637 yards in 14 games (1871 over 16 games). Valentine in S16 had 1392 in 13 games (1713 over 16 games). Looking at the top 20 individual seasons for passing yards per game, only 6 of them come from after the change. Similar is true for pass attempts per game, where only 5 come after the change. The pure numbers are higher yes, but Hall of Fame voters know the difference between eras, and it's per game numbers and most importantly how you compared to your peers.
Also the passing inflation isn't a sim inflation, but a correction from the very low passing seasons right before. You use S23 as an example, and S22 and S21 also are similar where the leaders had 1191 and 1281 yards respectively (in 13 games). In S20 the league leader had 1447 yards in 13 games, which in a 16 game season is a pace of 1781. It was pretty common for receivers to have 1400 or more yards in 13 or 14 games in the first 20 seasons of the league. Fyodorovich in S12 had 1637 yards in 14 games (1871 over 16 games). Valentine in S16 had 1392 in 13 games (1713 over 16 games). Looking at the top 20 individual seasons for passing yards per game, only 6 of them come from after the change. Similar is true for pass attempts per game, where only 5 come after the change. The pure numbers are higher yes, but Hall of Fame voters know the difference between eras, and it's per game numbers and most importantly how you compared to your peers.