Trend chasing and released too late. EDM was on the way out by late 2013.
Zedd was a nobody during the initial stages of ARTPOP and by the time it'd been released he'd already debuted, peaked and started working on his second record.
it was never fresh lmao she was always late with this EDM sound 2 years after its peak.
her great songs on the album (GUY, ARTPOP, Sexxx Dreams, DWUW, and Gypsy) are the only ones that have a unique sound. and to me those tracks still sound great.
The first and main reason I think is because Swinefest. Gaga performs her songs live in a much better way. So, while waiting for the studio and final versions in those 2 months, we got used to the live and raw versions. The studio version songs sound dull and lifeless.
Second I would say is that the universal hate probably got inside people's head.
I'm a LM myself, I love Gaga. But I can't listen to AP the same way I listen to BTW repeatedly. With BTW, Gaga wrote her music on piano, with ARTPOP, Gaga wrote her music on already made instrumentals (Aura, MJH, Donatella). Plus I hate EDM, it's like fast food. It's trashy. I think that's why the quality of the music declined.
It's because it's heavily EDM and not a lot of EDM ages well.
I agree with you about the title track 'ARTPOP', though. It's such a unique track compared to the rest of the album and still sounds fresh today. Really that, Venus and Do What U Want are the only songs that didn't age poorly.