I'm guessing GitHub's contribution insights sort of gave you this impression.
https://github.com/passbolt/passbolt_api/graphs/contributors
What I'm working on are developer insights and I've found the most intuitive way to look at contributions is to sort them by latest commits.
https://imgur.com/msfE9vS
With this type of display, you can quickly see who is contributing on an active basis, and for how long. A good example would be the vscode repository.
https://imgur.com/aX66Gj5
Here you can see a lot of developers have been contributing on a steady basis for quite some time.