I picked up a pair of the 700 X's a couple of weeks ago - no complaints so far. The replaceable cable removes the only weak point in an otherwise completely repairable product. That lets me amortise any difference across a decade or so.
Good point, hadn't considered this! Well, I bought the DT 990Pro in the beginning of 2023 and the MMX150s like three weeks ago, so I'll see for how long I'll use them :D
MMX150 are for the office because they're closed-back and the microphone is actually astonishingly good. At least people noticed in MS Teams calls.