The two aren't mutually exclusive. It is a common monetization strategy for open source projects to offer a paid hosted option in addition to free self-hosting. For example, you can self-host Matrix (synapse, dendrite, and conduit) but you can also pay the creators of Matrix to host it for you[1].
> The lack of a unified backend makes it much harder to build native mobile apps.
That response comes across as disingenuous. The lack of a unified backend makes a lot of monetisation models hard, but should pose zero problems for native mobile apps. Point at an API and done.
[1] https://element.io/pricing