There's a big difference -- that's how the PostgreSQL community works. 2ndQuadrant (now EDB), EDB, Citus (now Microsoft) all add value to open source Postgres, contribute back to the community by bringing new features, new life, usecases, and of course committing changes upstream where possible. Timescale is actually on the more open side of that balance, with the licensing and the community version feature matrix.
Also, in this case, Timescale actually has a pretty forgiving license[0] as long as you are not a add-nothing-aaS-provider, perhaps more than it should be, which I've asked about before[1]. Even before that change was made, running just the community edition as a add-nothing-aaS-provider would have been an improvement on the status quo, given how soundly it thrashed some other solutions in the past (ex. Influx[2]) and what you can do it (promscale[3]).
I know it can't be all roses, nothing is, but I don't think they've put too many feet wrong so far.
[EDIT] - I should note that on the scale of "contributing" to Postgres, the scale heavily tips in favor of 2ndQuadrant, EDB, and Citus as obviously they have the most committers and core team members. All those companies are to be commended of course, they're making postgres work as businesses and keeping it free while also improving it.
[0]: https://news.ycombinator.com/item?id=24579905
[1]: https://news.ycombinator.com/item?id=24585564
[2]: https://blog.timescale.com/blog/timescaledb-vs-influxdb-for-...
[3]: https://github.com/timescale/promscale