Mainstream superhero comics thrive on the illusion of change. Heroes are aways at the midpoint of their careers. Alot can happen in that midpoint, so there is no need to retire or age these heroes. Not if you want long term success with them. And that should be the goal. Every generation should experience these heroes in their prime.
For something like Superman or Batman, maybe. But
X-Men did well for a couple of decades with a continually evolving roster. It wasn't stuck with Cyclops, Marvel Girl, Beast, Iceman, and Angel forever; a whole generation's "first" X-Men team was Cyke, Wolverine, Storm, Nightcrawler, Banshee, etc. And that team went through many more changes over the years that followed. It went a long way without being reset to the original team configuration. Even when the original five were reunited, it was as a separate team, and it was still many more years before the old guard rejoined the X-Men.
And then there's Spider-Man. He went through many changes over the decades, from high school to college to grad school, from relationship to relationship and ultimately to marriage. Norman Osborn died and stayed dead for decades. It was later generations of creators who eventually came along and undid the changes.
So it's hardly fair to call it an "illusion of change" when it took something like twenty years for things to be reset.
Today it's an illusion of change because people's expectations are so locked in by the easy accessibility of collections, by movie and TV remakes getting back to basics, and just by the critical mass of the accumulated resets. But it hasn't always been thus. There was indeed a time when comic creators like Lee and Conway and Claremont and the like made genuine changes that they intended to be permanent. The fact that later creators decided to erase those changes doesn't mean they were merely hollow illusions at the time they happened.