SimpleAnalytics.com, Plausible.io, Matomo.org, GoatCounter.com, and (shameless plug but WIP) Chiffre.io.
However, while there is a competition to gain users and market share, ultimately these platforms are in competition against Google Analytics and other giants of the surveillance industry. The only risk if one of them grows too fast is that it becomes the new giant. Google used to say "don't be evil", after all.
I have been building a self-hosted platform [0], and I always get pressured into offering it as a SaaS. I am strongly against it and try to make it work by teaching people that self-hosting is really easy and it's the way of the future.
Your opinion will change in time. It all comes down to the principles of the company and who has control of it. That's why Fathom hasn't taken venture capital. As soon as you bring in people who don't share the same values as you, things start going downhill. You do not need to store centralized user data to run a sustainable competitor to Google Analytics
