I do. Admittedly I don't have thirty thousand, but I do have files going back to 2008 that I routinely re-edit. The software that is available now is so much more capable than what was available at the time that I can get much better results now. My view is that developing technology will constantly improve the results I can get from raw files so I never delete any raw file of any image I am keeping. It doesn't mean that I'm going to reprocess every one, but for those I want to reprocess I always have the option.
Funny thing: so many people complained before that exposure correction dial didn't work in full manual with auto ISO… and now it seems that only a handful of users noticed that Fuji fixed that in 4.0