https://communityhub.strava.com/insider-journal-9/an-update-to-our-developer-program-13428
The gist of it is that Strava just killed its free API, and will now require developers to have a subscription.
At Strava, we care deeply about developers, and the health of the developer ecosystem. There are now 241,000 Strava API developers, up from 185,000 last year. Starting today, all current and future applications will automatically receive access to the Standard developer tier. This allows you to serve up to 10 athletes and start building immediately, completely eliminating the previous queue.
This essentially kills thousands of tools people build using the free API.
If you’re looking to move away from Strava, so far I’ve found two open source alternatives:



There are lots of alternatives. Apple has one Garmin has one. Google has one. etc.
Garmin requires Garmin devices to be if any real use. Same probably goes for apple. The reason strava is popular is everyone can use it, no matter their phone/device.
Edit: not advocating for Strava or saying it’s good. I don’t like it, don’t use it anymore.
I think Strava is just popular due to cultural inertia more than anything. Garmin, Coros, Fitbit, Apple, even phone apps. Not really hard to export data and move. 90% of what I saw on Strava before closing the account was Zwift garbage anyway.