Tidelift actually asked several hundred maintainers who had quit or considered quitting an open source project. This article details the findings:
I don't think you're reading this and the previous chart's trends correctly. Whether a project has an initial jump in contributors or a slow rise, they tend to have a slow decline in contributors over time. That is OK. The only problem is when there is a big drop-off like you see for the Ansible project.
For context, I have been analyzing open source communities for 5+ years, and just wrote a few paragraphs last week: https://thenewstack.io/solana-blockchain-crashes-into-open-source-top-10/
