Other countries are not likely spending much less on the transition, it's just that they're paying for it more in tax and less in the electricity bill. The UK's strategy here basically means there's now a huge amount of investment in renewables even without government subsidies. And the nature of renewables and relying on gas in the meantime (which has pretty much always been setting the price of electricity, it's just gotten even more expensive recently) means that there's a relatively more painful period of investment before you get to the cost benefits of a nearly entirely renewable grid.