Old business proverb: "Never piss off your customers. They will go somewhere else and never come back."

I don't think you want to go where that proverb leads.

It would, for example, justify Kodak's decision to support the apartheid system in South Africa.

The customer isn't king nor always right.

>somewhere else

Could you be more specific?

Russian MIR isn't even supported in some places in Russia.

Chinese UnionPay isn't really relevant outside of China.

I don't need to be specific. I don't know what exists in all places. That's not my area of expertise. But I do know that there are other systems apart from the two you mention, Mir and Union Pay, that do work in countries other than Russia and China. Those Chinese tourists I see are using one or other of them.

And anyway, who's to say that there won't be another half a dozen new ones tomorrow that also do?

Too many in the West don't think other people can have any other choices than the ones that Westerners have. Reminds me of when the Japanese cars started arriving on the market. "Toyota? Mazda? What a funny name for a car! Mazda make lamps and lightbulbs, don't they?"