I believe the last time this was ever brought up by the devs in a PLL asking the same question. This was the response;
https://www.youtube.com/watch?v=KG5YxbKmbLI
NOW. This was back in Stormblood, and we can easily see what he's said concerning roles and balancing may create carbon copies, and what we see today in adjustments.
I'm not sure if he's gone on record to reiterate on this, but I think this is set as precedent that while Physick remains on SMN like a meme. They don't want to touch it.
And the thing to consider is Physick is an Arcanist spell that can't be ditched. When we sync down, both as SMN and SCH to < 30 lvl content, we retain the Arcanist Physick spell. SCH needs Physick to heal lower content. I can only see a future rework of SCH that takes it off Arcanist for good and becomes an individual job that starts at 30.