This is a bad take and the comparison doesn’t hold.
While Norway did see billionaires leave, and New York anticipates a similar exodus of wealthy residents, the comparison isn’t technically accurate as of policy differences.
Norway’s billionaires exited in response to an actual wealth tax - a direct tax on net assets. In contrast, Mamdani’s proposals target high incomes (a 2% surcharge on earnings above $1 million), corporations and property taxes - not net wealth. Given these differences in policy, the situations are not directly comparable.