They just never last. Arctic fans perform really well especially for their price but they all seem to develop problems. I have probably bought about 15 different Arctic fans from the F and P range and none of them survived 5 years, most were dead or developed noise within 1-2 years. Noctua on the other hand the old 80mm fan from the early 2000s still works just fine and remains quiet. Noctua fans are crazy reliable, they cost more too but I would suspect over the life of the fan they end up similar priced or cheaper.
Arctic fans seem to last 10+ years for me. I haven't bought any recently though and I run them at 500 rpm or so, that's my strategy: many and large fans, running slowly.
while arctic make fairly good high performing fans for cheap their bearings/acoustics are kind of bad. i bought 5 of the original p12 max fans with the ball bearings. they all made a chirping noise at various rpms (even after getting 5 new ones from arctic). the new p12 pro fans perform great but around 1200 rpms the motor is very loud and annoying
really wish arctic would now focus on the acoustics of their fans because its there weakest point. i wouldnt mind spending a bit more per fan if the sound profile wasnt just straight terrible which personally theirs are to me at the moment