Which country exactly? Oil-rich Norway has about 5 million people and is basically a democratic Saudi Arabia. Sweden has more billionaires per capita than the USA - quite far from the egalitarian society socialists dream about. And they all have strong capitalist economies, with multinational corporations and such.
> China
China enjoyed unprecedented growth when they decided to allow capitalism and free markets. Conversely that growth slowed and problems starting to appear when scared of the entrepreneurs success, Xi decided to reign them in.
Other A/B tests abound: Venezuela, North Korea, Cuba, etc. My favorite is where I live, Eastern Europe. We were starving until we got rid of our socialist economies in the 90s and how we enjoy what is basically a luxury lifestyle: flights, cars, iPhones, city breaks and vacations in Greece.
> planet is burning
Do you think communist countries cared about the environment? They polluted even more. Read up on the Aral sea sometimes. Mao killed all the sparrows to such an extent they had to import new ones. Caring about nature is a luxury only rich people can afford. And only under capitalism people are allowed to create value and enrich themselves.