The good thing about mixing is that it essentially happens off net. That is the big advantage of mix networks really. It happens inside the mix nodes RAM. If the attacker cannot see the state of the RAM on the mix node, then they cannot learn what is happening, even if they can see all traffic into and out of the mix. Replace "My private networks" with "The state of my RAM" and you have a mix network. There are much more efficient systems that can obtain nearly the same anonymity as this. The general concept is called PIR, the type you advocate for is everybody gets everything PIR. There are types of PIR that require several orders of magnitude less bandwidth, while still maintaining a high degree of anonymity. In fact, in some cases the anonymity of everybody gets everything can be matched while bandwidth required can be taken down orders of magnitude.