I may have misunderstood your question, if that wasn't the answer you were expecting.
My intention wasn't to evade.
Are you trying to ask the current status of Iodine mandate in India?
If so, then yes it is still mandatory.
In fact, almost every country in the world (around 126 from a cursory search) currently have legal mandates for Iodine in salt.
And I have mentioned the commercial aspect behind it.
Sure. But is it the ONLY aspect?
If most countries around the world are mandating something, then I think there has to be a good reason behind it.
Commercial can be one, but for such a widespread phenomenon, I think it's mostly health.
Countries in Europe which rank high in consumer safeguards are also doing fortifications. I don't think those countries would put commerce over human health.
If you hear hooves, think horses, not zebras.
They do unless you believe everyone has the exact same human body, genetics and health keeping the diet aspect aside.
I have said this again and again, if it were so, supplements wouldn't be available without a prescription.
Supplements do not affect anyone differently.
Only the absorption and excretion rates differ because of the factors you mentioned.
That said, (and like I've mentioned earlier as well), while the expressions aren't different, interactions can be.
If you are on medications, always consult a doctor before supplementing.
And if you are self-supplementing, always do an yearly bloodwork to check whether your supplementation is within bounds.
The fact that you believe that this blanket fortification works for everyone tells me everything.
Me and most countries around the world.
Anyway, this is it.
I have said all I've wanted to say on this topic and we are mostly going around in circles now, so there is no point in me continuing this further.
We both have our opinions on this and they differ, which is alright.
I'm not going to assume or have any inclination that we can make each other change our minds, so let's leave it at this.
Feel free to reply to this post if you want, but I won't be continuing further.