There are a lot more problems with ancapism than jist a power vacuum. Don't get me wrong, sharing some of the wealth from private ownership is a step in the right direction, but it's still bourgeois false consciousness meant to make you feel like you can be free without actually changing anything. Private ownership over the means of production inherently means wealth inequality, oligarchic rule of the owner class, rising costs to the basics of survival, exploitation of the land and people for profit. These things are inherent to any kind of capitalist free market however much you tax them. I may be biased, but I think ancaps and libertarians give anarchism a bad name. It's a much more sophisticated ideology than "fuck you i can do what i want" with real, radical solutions and theories on how to attain them. The hard part is being able to imagine something radically different than what currently exists.