I have to agree with this. Nothing against the characters who aren't coming back, but they don't fit into this story. It's as simple as that.
Getting most of them back in S2 was a stretch. After S1, most of the characters had no reason to stay together, much less still be on the same ship.
PIC as a whole wasn't designed like other series where the characters have reason to stay together long-term. The result is a series that's more fluid from season to season than we've seen in Star Trek before.
If PIC came back for a fourth season, it would be different even still. But now I convinced it won't be. Terry Matalas wants to expand the scope beyond Picard. So he probably wants a new series designed to follow up on everything TNG/DS9/VOY.
It's not the same as with DSC when Michelle Paradise inherited that series. She was handed a blank slate by the series jumping to the 32nd Century but had the same characters who had short histories and she could take where she saw fit.
PIC is the opposite. Terry Matalas doesn't have a blank slate in the 25th Century, he has to have different characters to make whatever he might want to do long-term work, and he has pre-existing characters with long histories where he can't do whatever he sees fit as easily because it has to grow out of something else from before that makes sense now.
Also, PIC has the '80s and '90s Trek Nostalgia Market cornered from the Movies to VOY. SNW has the '60s Trek Nostalgia Market cornered. If someone wants a Star Trek series free from all of that... Give DSC another chance. "STD sucks!" First I disagree, but either way, the series has changed a lot since S1. Ultimately for the better IMO, but that's just my take.