Says you
Correct, it is forcasted to decline by 2050
You need to check your figures.
Can you explain why? because not one Economist i have ever read supports this notion.
If you have less propensity to spend you damage Economic growth
In 1945 when Labour took over a country that was -256% GDP , they used Keynesian economics to borrow and invest. They built the NHS, They built millions of homes, they created the welfare state, it produced an economic boom that led to a Conservative PM saying "we have never had it so good"
The post WW2 social concensus created the boom years of our country, we built Concorde, we were leading the world in innovation, but who lost out out?
The wealthy lost out so they backed neo-liberalism and created a state that is now one of the most unequal societies in the world. The wealth of the super rich and parts of Manchester are amongst the most deprived parts of the country.
The problem with Socialism is people with excess wealth will have to part with some of it for the betterment of the people.