Capitalism doesn’t require democracy in order to function as an economic system. Indeed, it doesn’t even need a nation state in order to function. Aka Syria where the nation state has failed illustrates that capitalism still operates despite the difficulties it encounters in realising a profit.
However, where capitalism functions within a democracy the actual structure of democracy, and in particular the decision making process, must be aligned with the profit motive. Otherwise, no form of democracy will be introduced and capitalism will stay with the status quo whatever that may be.
Neither capitalism nor democracy are systems that most people understand properly. They represent a point or a section along a continuum that isn't a single line, it is more in the shape of triangle. Consider government. While the US may consider itself a democracy it probably has reached the stage of an oligopoly - ruled by a few people. I am Canadian so do not have a dog in this fire but I would say that the Bernie Sanders experience is representative. He was never going to be allowed to be the "Democratic" party candidate for president. On the other side, I still remember Trump's first announcement where all the people in the audience were actors.
At the other end of the scale the "Communism" of China is an oligarchy as well ... a government run by a few people. At the third point "Theocracy" ... I imagine Iran might be an example where the government is run by a few people as well. Democracy is somewhere in the middle of this triangle where the people actually retain the power ... outside of the hands of a few people.
The same dynamic can be said of business. Who controls the wealth. In the US once again I would no longer say that it is a capitalist system. The lines of communication is owned by about 6 companies, the majority of sales is probably in the hands of 2 or 3 companies. I cannot even say what country is working under a communist system ... although possibly Belarus except its leader controls many of the reins and I think luckily he seems to be a benevolent dictator. As far as theocratic economics, I hope that the last one that we saw was in the dark ages ... where the churches tithed the population ...
So capitalism like democracy in my opinion are just islands and I cannot be positive that they exist in any population greater than about 1 million people.
Capitalism without Democracy rarely provides the 'free market' that is one of the pillars of Capitalism. I actually feel that the two will seek each other out when the conditions are right.
Singapore. One of the wealthiest (per capita) nations on Earth.
(This does not mean that Singapore is undemocratic, but that is what economic freedom without political freedom would look like.)
Democracy refers to a system of political power, free-market capitalism refers to liberty to own and exchange property. They are two different things.
Of course they are two different things. That is how they can possibly be married :)
Please note that I never used the term Free Market Capitalism, I used the much broader Capitalism in every instance.
And one more thing. Thank you for the excellent comments and the willingness to exchange ideas. The very reason I wrote this post.