Nobody paid a 91% tax rate in practice. What a silly thing to focus on, a headline marginal tax rate nobody paid.

The 1950s were great for places like the US, Australia and New Zealand because they were initially fairly unregulated (wartime planning was ended and the market took over) and they weren't destroyed by the war.

The UK had rationing into the mid 50s while its empire crumbled. It was not some heavenly place. Millions left the UK for the new world, including my grandparents, because the UK was in a dire state.

Over the next 20-30 years, the anglosphere became progressively more regulated, more taxed, more controlled, and more unionised. You needed a licence to import a new car. You needed a licence to import magazines. Exchange rates and interest rates were controlled by the government and adjusted for political purposes. Large parts of the economy were run inefficiently by the state as make-work schemes to prop up "full employment" policies that were politically popular but very expensive. The oil shock of the 1970s revealed how bad this scheme of economic management was at responding to changing conditions. When you have thea biggest economy in the world and you were untouched by a war that decimated your competitors it is easy to look good. But the system was not capable of responding to changing conditions because it was largely driven from the top down by bureaucrats and politicians for the sake of implementing their preferred social policies and winning elections respectively.

In the 1980s, this came to a breaking point. This was true everywhere, but the clearest example is not the US or the UK but New Zealand. It nearly went bankrupt trying to maintain completely unsustainable exchange rates for political reasons and there was a small consitutional crisis when the outgoing government refused to implement the incoming government's instructions to lower the exchange rate. The economy was dominated by what were called "Think Big" schemes: government infrastructure projects that made no financial sense but looked good on election posters and "created jobs". Large numbers of businesses did entirely pointless things like assembling Japanese cars from components more expensively than could be done in Japan, because car imports were restricted. Many other examples exist. Agriculture was heavily subsidised by the state.

The new governments in the 1980s (I am talking about the West generally now) did away with much of this rubbish. They lowered trade barriers, reduced or eliminated subsidies, and privatised the elements of the public sector that had no reason to be run by the public sector.

Sometimes when privatised these businesses failed. But that wasn't because they were privatised, it was because they had never made any financial sense in the first place.

The fundamental point is that the 1950s system was the same as the 1960s and 1970s system. If you go back to the 1950s, you also go back to the 1970s. The system was the same, the same incentives would exist, and the result would be similar. Give the economy over to the public sector and in a few years all thought of making what customers want and will pay for is substituted with using economic power to achieve social goals and win elections. We had better make sure we hire more Xs, they deserve more representation, and we better put money into Y, people love to hear about Y, and so on. And before long it is a lumbering inefficient mess.