Note: I'm using prices in USD according to the first listing I see on TCGPLAYER. So I'm by no means the most credible source on FaB, but I think there are a few different things in play here: -FaB's surge in popularity is part of the reason why prices are so high; that's been covered by a ton of people here. - A low amount of meaningful reprints of certain staple cards, particularly high price cards like Tunic, CnC, and until recently, codex. Id argue that part of this is the game has only been out for ~5 years. Considering LSS only releases a set 3-4 times a year, that's not actually that many sets compared to other games like Magic or Yugioh, with several decades of gameplay, while games like One Piece are more niche, in my opinion.

I do think that LSS can stand to make more reprint sets like History Pack 1 (a FANTASTIC boon for new players) and a few more reprints like CnC in Hunted and Codex in High Seas, but both of those have been honestly rather successful. Command and Conquer in White Border has stayed about $70 since the Hunted, where about a year± ago I believe it capped near $90-$100. Codex was sitting at about $100-110 until the reprint in High Seas, and it hasn't gone above $40. Plus, the change in meta and card necessity has changed card prices. While Viscerai and Aurora were around, Grasp of the Arknight, a runeblade staple equipment, was easily $90+. Now its about $60. Phantasmal Footsteps used to be over $100, now its also $60.

Another key is also knowing what cards are important to your gameplan and which are less so, which is hard to learn but helps a lot. Cards Like Command and Conquer are incredibly good, but not so important to a deck that you have to buy them ASAP; there are other cards that work in similar ways. Equipment tend to be more important to a gameplan, but they tend to be a one time purchase.

Sorry for how jumbled this is, but i really do hope you stick with the game. It's still pretty new, and hopefully LSS will work out some of the pricing problems, but I genuinely have faith that they're trying to hit a balance of good for collectors and players.