I mean, on your first point, it's an automotive grade part. I think any eMMC put under these conditions (75% full and the other 25% written heavily to with log files) is going to have a relatively short life expectancy.

What baffles me is that who is reading these logs? Can't they just turn then off (pipe to /dev/null) and then have cars that need troubleshooting put into a debug mode at some point?