What happened to themed icons? Is android going back?

Themed icons can be so good, if they were implemented across all apps! But major app like Hotstar, JioCinema, Airtel, Zoom and even Google Fit doesn't support it! One UI 7, now has *3D* icons, are something- Is this the end of material you? It never got implemented properly outside Pixel and even there many apps make it look out of place.