As to the second point, I think it's a stretch to call any of those things "reboots". The Klingon War lasted through the first season, and then they shifted to a different storyline for the second, which seems pretty standard for any modern TV series.
And it's pretty clear they had been building up to that jump to the future since the beginning, what with all those mysterious time crystals we saw in the opening credits (although apparently the original plan was to only jump forward 300 years instead of 1000). And Kurtzman hinted from the start that they had a plan to resolve the canon issues people were having, with the spore drive etc that no one mentions later on.
So I just see these as the writers shaking things up and constantly trying to keep the show fresh. Because modern series can't get away with the super formulaic storytelling we used to always see in the 80s or 90s.
Ehhhh....I'm not so sure I buy that it was "planned from the beginning," though Kurtzman would probably like you to believe that.
Remember the upheaval that plagued DSC behind the scenes from the beginning. Bryan Fuller is the showrunner, plans out the first few episodes, then leaves. He's said in interviews that he WANTED the show to be an Anthology (like American Horror Story), with each season tackling a different part of Trek we haven't really seen before, with the first season being the Federation/Klingon War, and that's how the first few episodes were originally written; but CBS didn't like that (it's harder to market that way, which I completely understand). Then there were the other two showrunners that came in, Harberts and Berg, and shifted it away from the Klingon War as soon as they could - it was pretty clear there was a shift in focus around the 4th episode or so (as soon as Fuller's scripts were finished shooting - there was pressure to get the show out the door, so they had to shoot what they had). The War didn't even last through the first season, if you recall; it got wrapped up with a bow around episode 10, only for them to proceed to wrap up the first season with an extended stay in the Mirror Universe.
I agree it may be reaching that the Enterprise/Pike/Spock addition in season two may not have been a soft reboot (I said so in my last post too). It IS common to try to add popular existing characters to a show that's struggling (see Worf in DS9, for example. Q in Voyager). But I'm not 100% sure that's what was happening.
Anyway, Harberts and Berg set up season two and even gave interviews about what they were planning with a scientific mystery, and it's clear they set the original starting point for the second season and had a significant amount of the season-long arc in place. Then they were fired, supposedly over harassment, and Kurtzman took over, and has been in charge ever since. To me, it's pretty clear that Kurtzman was the one that changed the direction of the second season toward leading to a future jump, and that was his soft reboot.
Maybe it's possible that Harberts and Berg intended for there to be a time jump too? And that's why those crystals are there in the credits? I don't see much evidence of that in the scripts, but it's definitely possible. But, as you yourself said, Kurtzman definitely at least adjusted that plan from their original idea (300 to 1000 years). I definitely applaud him for it. I think DSC has gotten a lot better post-jump, and it finally reconciled for the most part with canon.
So, I stand by what I say. There's no way Kurtzman could've planned anything from the beginning, because he wasn't there. Fuller point-blank said what his plan was, and everything after the War wasn't it. So from my viewpoint, that's at least two soft-reboots (one from Fuller pivoting to Harberts and Berg, another pivoting from them to Kurtzman).
Now, all that is really about behind-the-scenes drama. It's possible that none of this has anything to do with viewership, or anything outside the writer's room, and that it has nothing to do with how successful the show is. It just...doesn't look good from a "how successful is this show?" point-of-view.
Short version - Here's the breakdown:
1. Shows often add new/popular existing characters to boost viewership
2. Shows often soft-reboot to boost viewership
3. DSC has done both
4. 1 and 2 do not necessarily mean DSC is unsuccessful
5. Without viewership numbers, we know NOTHING beyond anecdotal evidence, so this really means NOTHING.
Maybe we just disagree about what a soft reboot is, and that's cool too