[Isofarro]

They already "open companies elsewhere". From the article, the non-dom status is a tax-exemption on a non-dom for profits and revenues from businesses outside the UK.

If these non-dom billionaires leave, and they aren't currently paying tax, will we even notice?

The housing market noticed; again from the article, the value of properties valued above £10m dropped by 37%. So these "just leavers" aren't just leaving, they are taking a near 40% hit on selling up.

[DoesntMatter22]

So then leaving is giving the government less tax revenue and hence less money for other people