There's a difference between genuinely cancelling a book and then bringing it back at some point in the future with a new #1. I also think it's a different thing if you fundamentally change a book and decide to relaunch it with a new #1, like bringing in Kyle Rayner as GL or bringing back Barry Allen or replacing Cap with Bucky.
Okay, I see what you're saying. But while you and I can understand that difference, I don't think it's all that perceptible to the wider reading public. They just see decades-old characters in titles that started very recently, either way.
And to the extent that it is perceptible, I think changing the identity of the main character is WORSE for public marketability. When somebody has just watched a movie or TV show and liked a character, it does not help if they pick up a comic, looking for that character, and find out that, oops, now it's some other guy.
Now, it's one thing if a creator is doing their own version of a character for a limited series or one shot, like Frank Miller's Dark Knight Returns. Those standalone stories can vary from the established canon in all kinds of ways, and still do pretty well as evergreen bookstore properties. But when publishers keep messing around with the ongoing series, that's when chasing the monthly comic shop sales becomes counterproductive to longterm success, in my view.