I find this statement amazingly weird. In my experience, MySQL's access grants are extremely impoverished compared to Postgres (even in 8). It doesn't have row level security either.
> The main issues with managing Postgres today are grant inheritance
roles + `INHERIT` (which has been available since at least 8.1, 15 years ago)
> I shouldn't have to update grants for non-admin or readonly users after adding new objects
You don't. There are default grants that apply on object creation within a schema: `ALTER DEFAULT PRIVILEGES`.