Imagine if we had a government board deciding what prices people could charge for App Store/Google Play Store apps. (It's not like we're talking about radioactive waste or something involving externalities, where government regulation might be justified.)
No, it's to fight for what they want (or perhaps think they are entitled to) to control.
“Property” is simply what the government says you are entitled to control.
Sure, everyone had their own theory of rights. And if by people acting to defend their property you mean “people will fight to secure access to those things to which their own personal theory of rights holds them to be entitled”, well, you’ll notice that's exactly what I described, but not at all what people mean when discussing “property” normally.
In the united states, the biggest things affecting the poor are healthcare and housing costs and remarkably those aren't what most people consider to be the 'rich'. They're systemically broken with corruption and waste.
And as for all business models are based on government, well that's absolutely wrong. For example the existence of black markets -- those in violation of the government seem to show that they they don't rely on the government. Let alone any type of service business.
If you want to argue that government is necessary for property rights to exist, that's a resource saving measure - people protect their property all the time when governments fail them.