I know a long time ago they were the best FP producing buildings in the game, but still seeing them in 15 fragments makes me wonder if they are still very special. It is much easier to get better FP producing buldings nowadays.
but still seeing them still in fragments makes me wonder if they are somehow still very special.
Finally, why this building still kept and why this building fragments still kept in the game already answered by @Emberguard very clearly.The game is meant to be played over time and have a element of strategy.
All they need to do is introduce a new level every 6 months to keep up with % inflation.Because Inno doesn't really consider it important to update deprecated buildings, there are still many things that work the same as many years ago.
E.g. 1 FP still costs 50 diamonds. Not that it was a good idea to spend diamonds on FPs like ever, but back then 1 FP was a "big deal" (speaking of SoK, right? ). Medal rewards are also a joke for many.
Maybe Inno will eventually adjust the Auction Dealer too, the items are quite outdated there too, for endgame players there is pretty much 0 items there to buy (for new players there are still "plenty".