USD $1 million + tax on the worldwide income of a millionaire for 5 years + spending of a millionaire in the national economy for 5 * 182 days + tax on the worldwide income of a millionaire for as long as he remains a citizen plus 10 years afterwards
In UK's case:
£1 million + tax on the worldwide income of a millionaire for 6 years + spending of a millionaire in the national economy for 6 * 182 days
You mentioned 2,3,4 years for the indefinite leave to remain and the powerful non-domicile tax status, all of which are true but irrelevant to this analysis. Anyone trying to gain citizenship through the investor program must be a tax resident for at least 6 years.
In Canada's case:
CAD $0.8 million + tax on the worldwide income of a millionaire for 3 years + spending of a millionaire in the national economy for 3 * 182 days
In St. Kitts's case:
A one time payment of USD $0.25 million