Property is an informational concept more than a legal one. The concept of "mine" is present at a very young age, and clearly present in various animal groups. The data-structure is a simple association of objects with an owner, and for the substrate animals use only their brains, but humans use paper and, increasingly, bits. Banks and local government agencies keep the most official of these records, but informal records count too. (My son may think my daughter's blanket is his, but she will protest loudly and vehemently, and there is not really a formal reason for her claim).
concept of property...is the sole mechanism through which massive disparities in power are achieved and maintained
Property is a necessary, but insufficient condition for inequality. Property is how you keep score; the reason some players win far more than others is not entirely known, but I'm pretty sure it has more to do with personality, talent, and luck than the jurisprudence of property rights.
It's not clear what a society without property would be like, BTW.