If you do it once every decade or two, it's gonna be fine because you're dealing with a new generation of readers.
But DC, and to a lesser extent, Marvel has been extremely reboot happy the past few years, it's gotten to the point where I just got done with Comics, and only read comics that are standalone (for the superhero variety, this means stuff like Earth One for example). Both have been crossover happy as well, and it's got to the point where
Manga is far, far better about this, retcons are extremely rare, and the only actual manga reboot that I can think of is the ending of JoJo's Bizarre Adventure part 6. Every series is self-contained, so it's easy to follow with minimal crossovers, even if this can result in long-ass series. Now manga has its own problems from a business-perspective, primarily to do with the way labor is treated, but those are far easier to fix than US Comics' issues.
To add to what you said, there have been multiple adaptations to the comics in television, animation, and film thus there are generations of fans whose love of Marvel/DC character comes from
Superfriends, Spider-Man and his Amazing Friends, and the entirety of the DCAU. Additionally, with the rise of legacy characters it has fragmented the fandom between fans of different incarnations of the character and
Green Lantern suffered from this after "Emerald Twilight" turned Hal Jordan into a super villain and put Kyle Rayner in the role. Hoo boy, and then there are the John Stewart fanboys who have to stake their claim.
Case in point, there was this guy I have mentioned before. An obscure journalist/critic from Virginia that I have sparred with on another forum who has a massive hate boner for the DCEU, Geoff Johns, and anything Silver Age. It is clear that he is a fan of the DCAU's
Justice League because he never stopped complaining about how boring Hal Jordan/Barry Allen were and how much John Stewart/Wally West were more "fun." It really never really occurred to him that A) the comics and DCAU were different entities, and B) that Hal/Barry had their own fans as well. He would go on about much better things were when John and Kyle were the only GLs with Hal nipping at their heels. When I pressed him on what issues he was talking about, he would refuse to answer the question or make some excuse that he had the issues in a longbox.
FLASH FACT: John Stewart was reduced to a powerless supporting character from "Emerald Twilight" in 1994 to around 2003, when Kyle left for space. Similarly, Hal Jordan was only active as Parallax for a few months until he "died" in
Zero Hour, and reappeared in
Final Night to die again. If you look at Hal's history from 1994 to 2004, he spent more time as the Spectre than he ever did as Parallax.
Basically, his arguments came down to
"muh childhood" and appeals to his own authority as a journalist. The comic book community is infested with fans like who like to act as gatekeepers or taste-makers.