It's been mentioned below that differences in temperature matter a lot. But there's also the fact that erasing a flash block inherently damages it, progressively reducing its ability to retain data.

So I wonder if there's a tradeoff between longer data retention when powered off (by using higher write and erase voltages) and longer MTBF (by using lower voltages). I could be completely wrong here, but if there is such a tradeoff it would make sense for consumer and enterprise drives to make different choices.

On that note I've always wondered if putting an SSD in an oven at the highest temperature just before damaging it could revive it from being written to and erased too many times.

The same mechanism that makes SSD's not retain data (that is, the electrons escaping) and the same thing which makes them not retain the data that you do want to keep would presumably also make the electron buildup that you get that kills the cells abilities to continue their write/erase cycle.