My assumption was right about the "plastic"... they cracked and broke and had to be glued over and over... decided to go for a bit higher quality and got these around May 2023 (gee, I've got a big backlog of "stuff" to post about on social media...) and the only complaint I've got is the bluetooth range, but that's liveable...
"Sony WH-1000XM3" 2nd-hand via CEX again (just like
these) and I've been using them every day, basically, with similar to my earphones (link earlier) equalizer modification to flatten the output using Wavelet on my phone and Equalizer APO on my laptop which takes out the "curve" put in my Sony and (and EQ APO boosts the output to be as loud as these old Koss & Monoprice headphones) the output is as though the EQ was "flat".
The plastic hasn't fallen apart once with these, which is great! Sound quality, ANC, comfort, ease-of-use, all are excellent on these, everything is better than the monoprice I had, as it was clearly a cheap imitation.
The only thing is because I've used them SO much, that the ear-pads are starting to degrade haha. I'll just replace them and continue on, I think.
At the same time, I bought another one from CEX as a "backup", going by the dogma of "one is none" (e.g. when one breaks, you've got none, so you need at least one backup/redundancy) and bought these too, "Sennheiser Momentum 3 Wireless" (first one I bought had a problem: right-ear is about 9dB lower in volume than the left-ear, which I tried to compensate with via EQ/PreAmp setup mentioned above, but it still sounded horrible out of the right... so I returned it and got a perfectly-functional replacement which is the pictured one:
Have hardly used these ones, but they go good on a plane, for example.