Also agree with the sibling poster - I like subscribing to support them on a regular basis (and of course Catalyst).

In addition, the Git plugin, coupled with Working Copy on my iPhone and iPad, also work extremely well, with a bit of added overhead. Though iCloud works reasonably well for just about everything else, I haven't used it for syncing Obsidian data.

The tradeoff doesn't make sense otherwise. If you're poor, then you wouldn't have the luxury of the available time to write your own PKM - the opportunity cost is huge, it's massively preferential to use an existing free solution that is "good enough" (Obsidian without sync or using your own sync solution, Dendron, Roam, Org). If you're not poor, then $9/month is a rounding error, especially compared to the value provided.