[mike]

This is a subject I haven't heard or read much about in a long time. DNG was going to save us all if I recall. ? To date, I don't know of any raw format that can't be converted one way or another. Most, if not all, are still covered by the big players. There's not that much code to carry along (probably for my lifetime anyway). I also don't believe you'll ever not be able to convert a raw file. Besides the big players, there's plenty of open source code and plug-ins (rawpy) out there. Which makes it easy to convert all your files to something else, provided you have the disk space to save it all and don't mind writing a handful of lines of code. But it all leads to essentially your second question; how do you do this in a timely manner?

TBH however, at this point I'm not even sure how to go back and really look for or browse all my old raw files. Everything before the last 10 years isn't easily accessible either by finding it or remembering it.

My methodology for this, and take it with a grain of salt, is to keep all the raw files along with edited files I printed or shared. If they're just vacay/fun shots I printed or shared on social media, I delete most those. Nowadays, the saved edited files are full res jpegs being I generally print jpegs. I also can't see jpeg going away anytime in my lifetime.