Around the pandemic the GameCube just took off people were finally giving it a chance it’s also supply and demand it didn’t sell well so it’s not like buying a PS2 which are everywhere so the cost rises as a result.
I have a feeling the Wii U will become a collector’s item in a few years to based on it failing at retail systems that fail at retail have a tendency to be sought after decades later like the 32x, Sega CD, Jag, 3d0, apple Pippen etc while systems that were plentiful and sold great at retail can be picked up for cheap years later like the nes and SNES all PlayStation systems etc are all very affordable even if game prices are creeping up