My bet is that this is going to change a lot, very soon.
Apple apparently felt comfortable enough with the eSIM situation in the US to drop legacy-SIM already. The fact that they couldn't do this worldwide yet is because, as you say, eSIM availability is still spotty around the world.
However, the fact that they're moving to eSIM-only is a huge flashing warning to telcos around the world that the time to sort out their eSIM support is now. Otherwise, they'll soon be chasing away their affluent iPhone users.
I think the transition will now proceed pretty quickly. Physical SIMs have only continued on due to market inertia.
In a few years we'll look back and think "remember when SIM cards were physical objects... that was weird wasn't it?"