There is no one definition of cancel culture. Many people don't know what they even mean when they talk about it.
If we break cancel culture up into roughly before the internet and after. Being canceled (I'd call a non-violent black-sheep status) was a local phenomenon, it was in your town, your church, or your local group. You could move away to reclaim anonymity.
Today, you can't hide from it, but it's as you said, a quick burst. But I think you're forgetting that these ramifications aren't just about you being hated by the internet, they can follow you by alienating friends/family. They have made people lose jobs. They take a person's worst moment and give it permanence in a way that wasn't possible in the past.
I'd probably say that cancel culture requires the internet to really be a thing, because now we can take anyone who's worst moment is caught on video and have it follow them around forever. Sure the internet as a whole might not hate you for more than a week or so, but the ramifications of unwanted massive celebrity must be profound.
To be clear, I'd consider cancellations to be people who are not famous and don't want to be famous. Even that level of positive reception by half of a socially powerful group might be unwanted, especially if you don't really align with them.
I'll finish with this, cancel culture is a minor problem compared to those of our ancestors. But it's still something we as a society can try to work on. As individuals when we see someone being canceled, don't dog pile on them, look for context and dig deeper. Sometimes it will make you more angry there are people you're not going to like out there.
Side story: When I was a kid I had a bully for all of 1 year in elementary school, he'd trip me at recess every day. One day I lost it and punched him in the face. I remember this clearly, he waited a few weeks then tripped me one more time. For most of us that'd be the end of the story, but a few years later, a family friend of mine brought him by our house and I had to play with him for an afternoon. We got to talking and playing. Just two kids playing as if we didn't know each other. I found out he had dealt with some shit I never had to, and it showed me that his behavior wasn't all his own. I don't regret punching him, I don't begrudge him being a bully for a year, but I do thank that family friend for giving me an afternoon of seeing more context. It showed me that, I don't have to like everyone, and I don't have to let people walk on me, but I do have to do my best to understand people even when I don't like them.
Sorry maybe that's not relevant, but I think about the kid that I was getting thrust onto the internet for punching someone, no context, no background and I'd probably not have learned from it.
Edit: context around the link. Just a really good video I watched from a person I like on this topic. Sometimes I'll haunt my threads to reply to people but I don't really feel like it tonight, so have a good night everyone.
https://www.youtube.com/watch?v=p26JJxvw4lM