Tbh, I’m okay with exclusive (cosmetic) seasonal content.
Games are expensive. A good online multiplayer game requires a stable revenue source and a huge active player base. Seasonal content is one of less scummy ways to achieve both. It spreads the costs better than milking a small number of whales and it incentivizes the average player to play on the regular.
Imo, losing out on a skin cause you didn’t buy/play a specific season is decent trade off. You don’t need to own everything you want.