On the reboot thing in general, even though Marvel technically only has one continuity all the way back, there are sort of reboot-like retroactive changes to continuity and to the status quos very frequently. I think both companies have found that these result in sales jumps that then subside, and are into a cycle where they do them every so often to get the next bump until the steam goes out of it, and then do it again.
On the Marvel side, as an example, they are constantly changing the names of the X-Men books and which mutants are in the teams that make them up. People die and come back constantly. There are a ton of variant versions of each character. At one point, the main Wolverine was dead, but there was his female clone taking the Wolverine mantle, an older version of himself from an alternate future on various teams, and the son of a Wolverine from a different alternate universe all running around with claws- and I think I'm missing a few. Cyclops was dead, but there was a 16 year old version of himself brought forward in time who they were unable to return, plus a daughter from an alternate future that he'd had with Jean Grey (A different alternate future than the one Old Man Logan was from, even though they were at one point on the same X-team!).
There was one funny moment where Rachel Summers-Grey, who appears to be in her 30s, calls teenage Scott Summers (Cyclops) "Dad" and he says something like "Don't call me that! You're creeping me out. You're older than I am.". I also remember reading one where Old Man Logan is sitting on some bleachers wanting a baseball game with Jimmy Hudson, the son of the Wolverine of the Ultimate universe and they have a brief exchange where they recognize that they are kind of is some weird way father and son, but not really, and both grunt "Huh." or something and resume their day.
People have a love for these iconic characters and stuff, but they tend to lose interest if things aren't shaken up once in a while. The shakeup brings back readers who left for one reason or another and prompts them to give things a fresh look. Maybe it keeps people engaged who drifted off a reboot or two back by bringing back something or someone they liked from back in the day. Then the next reboot brings back what someone else liked that was absent from the previous reboot. I think what they want to prevent is where it's been like 10 years and people are so far removed from fandom that they don't even hear about changes and can't be reeled back in regardless of what is done. They might figure people will stick around comics in general and complain for 3-4 years reading other books and taking a look in on the stuff they abandoned once in a while, but not for 10 or 20 years. So they reboot every few years.