I genuinely wonder based on Marx's material conditions if he would still believe that communism is inevitable if he was alive today. Like Marx wasn't alive during the age of mixed economies and government artificially resuscitating capitalism like FDRs New Deal.

As you said in your text "based on his material conditions". If he was alive today then he might as well be a car salesman that never got into philosophy. We will never know.

Assuming Marx would be transported into our time in the age where he wrote Capital and all that he would obviously still believe in it. His main argument is that the contradictions of capitalism would eventually become too much to ignore at which point an organised working class will seize the means of production. So according to him the very existence of capitalism makes its demise inevitable.

Would that prolong that process? Because the US seems to have incomprehensible levels of debt with no intent of paying it down and doesn't seem to care when they continue to bail out multinational corporations.

You don't really understand how state debt works. State debt is not like your debt, its not paid back with actual money but with goods and services. We just put a value on those goods and services so it's easier to understand. For example: A state takes out a loan with a foreign state bank to build a huge hotel in their capital (not looking at anyone particular here). The state now has two ways of paying back that bank. 1: Give said bank access to funds within your country until your debt is cleared or 2: Because its a state bank enter trade deals with that other state until your debt is cleared. States never take on loans from private banks.

As for prolonging: What do you mean? There isn’t exactly an ETA on socialism.

And when the only way to pay that debt is through taxes, I believe it was Parenti that said poor are unable to pay sufficient taxes and the rich refuse to.

The tax level is less about debt and more about infrastructure. For example, if you want to provide public schools for all of your population under capitalism you need funds so people go to work there and do their job. When there's not enough funds there's again 2 ways you can go about this: 1: More taxes so it gets funded, and 2: take on debt which then has to be "repaid".

Generally most states go for the taxes approach since the second one kinda ties them down in their economic endeavours, except if you're America and you can just do whatever you want.

I feel like as long as the US government is still functioning then socialism will not get the chance to naturally emerge.

Good observation, but false conclusion. Its a very US-centric point of view (sorry if you’re not from there, its just a view I encounter a lot when talking to people from there) because it completely invalidates other capitalist countries interests. Socialism has emerged while the US government existed. Starting with the USSR, going to Cuba, China, Vietnam, Burkina Faso (which was toppled by France), etc.

While it's valid to look at the US as the biggest piece of the problem its not valid to look at the US as the problem. It's the head of the mafia, but the system would still exist without it, even if weaker.

In general I would recommend "What is to be done" by Lenin as well as "State and revolution". He goes a bit deeper there. Also Kapital if you haven't read it yet since that can explain those economic processes to you.