OK - now is this the answer to my question why mass storage was naturally supported on both the N900 and the N9 but isn't on the Jolla Phone? Because the Nokia models hat FAT partitions that the Jolla has not?

(Don't get me wrong, I'm not trying to argue in favor of FAT now or anything like that. I just felt that the explanation "everyone's moving away from mass storage in favor of MTP" is not satisfying for someone who used only mass storage on all Maemo devices so far, including Maemo 6. I can live with a good explanation why Jolla didn't include mass storage, as I could live with the N900 not supporting MMS given its complexity. I only feel that "everyone's moving away" isn't a good explanation.)