It has always been this way. They don't want you to be able to pick the newest units. It makes sense, the newest units are most likely the least available units as there's been no reruns, and no opportunity to be randomly summoned. I wouldn't want to sabotage my money earners either. If they changed the name of the selector to RGB selector rerun-only non-limited non-collaboration edition, would that be better? I know it is disappointing expecting something to be on it and not being able to get it. I really want Brieg (for free) so I'd be all for it. But if they did that, I'd personally say they would have no business sense at all and they'll probably go bankrupt with decisions that doesn't prioritize money-making, before any imprint drama kills them.

The newest couple of heroes are always excluded from selectors. You also can't do the story summon for new heroes for a few months. I can't do a story summon for Brieg until I think March for example, since I skipped him knowing that Lilias was coming up. :'( Hoping I roll him randomly, lol.