My take on that is that JJ and Terrio rewrote and reshot so much that the scenes that ended up getting deleted didn’t really match the rest of the film.
This. I can’t think of examples off the top of my head, but I’ve seen deleted scenes from multiple films throughout my life that were clearly deleted, rewritten, and refilmed before the rest of the movie was set in stone, menaing that deleted scene no longer can function in any version of the film since the scenes that supported it (or that it set up) were never filmed.
That’s got to be the situation for RO, Solo, and TROS - these movies were clearly so much in flux during filming that most of the scenes that were cut are so incompatible with the remaining scenes that they probably start subplots that were never finished, or include characters that no longer exist (Matt Smith, anyone?), and Disney doesn’t want to show just how much changes happened during and after filming, so they just skipped on including any deleted scenes.
I imagine we’ll see them eventually. Once having demonstrable evidence of how much tinkering was actually done can no longer negatively affect revenue in a significant way.