Global economic output is $80 trillion. There are 100s of millions of scientists, engineers, programmers, technicians in the world. Aside from the ideological complexities, which are probably intractable, it seems like it would be pretty easy to me.

What would it really take to provide basic housing, food, water, clothing, energy, and medicines to 7 billion people? Robotic automation, free / cheap energy, and access to natural resources.

The difference is that the owners of the capital aren't willing to lose on their investments, and it's cheaper to bulldoze and throw away than to give it away or provide work maintaining the communities that these properties exist in/on.

People can do whatever they want to their property, no?

Do you personally allow homeless people into your house?

Problems you mentioned are real and tough, but the objections are very simplistic. Its very easy to demand others to do something, and distance yourself away.

There is a long and historical precedent for demanding that people with excess amounts of capital owe a greater portion than those who own relatively little. There are material differences between the capitalists and all the rest of us, and those allow us to demand specific concessions from them.