There is quite a difference between democracy and socialism. For example, while democracy did not work in France, there were several other countries that have proven democracy works. For example, Greece, Rome, or even United States. On the contrary, socialism has been in many countries and failed every single time, no matter the situation. Countries of Warsaw pact tried it and 30 years after it collapsed, the quality of life in these countries is still worse compared to the Western Europe. Similar with countries such as Israel, India, Great Britain, North Korea and many more that have tried socialist tendencies but eventually returned to capitalist economies.
Same for capitalism, there have been countries that became quite successful thanks to it such as Switzerland, Singapore or Ireland.
First of all, you said regular people cannot benefit from companies’ growth, which is clearly false, because as per my previous reply, you can easily buy their stocks and become one of the shareholders. They even pay you dividends and your wealth grows.
Second issue you mentioned can be easily fixed by having competition in the market. When there are more companies, they have to improve conditions for workers, otherwise they will end up working for the competition. If no company in the market does it, thanks to capitalism you can start you own, offer the best conditions for your employees and they will come to you from the competition. Last but not least, whilst I agree lowering taxes does not necessarily mean rising people’s wages, it at least motivates people to start their own company (which creates more competition and that’s what we want). And yes, people who run the company are equally as important as the workers. It’s literally their responsibility to make decisions regarding the company’s direction. If you have a terrible management, the company goes bankrupt and workers, just like the people who run the company, lose their incomes.
With last statement I agree, US has the space to invest into free medicare, however at the cost of having less influence over the world.