Each one of them has wound up needing the plug replaced, and in the case of the Sennheisers, the connection of the wire to the ear cup just got intermittent, even with replacing and tweaking. One set of the SR60s also has an intermittent connection in one of the wires near the split. I was pondering pulling themm apart and grafting in another cable, but the ear cups don't seem to come apart.
So, yeah, they last a while, there are some replacement parts, but at some point they're still e-waste.
On the other hand, making the shift from crappy earbuds to good headphones probably saved my hearing, and I wish I'd done it sooner.
It warms my heart to see youtube reviewers who encounter them and are shocked at how good they sound for the price.