Do you understand the concept of MAC address obfuscation? When you configure a virtual server hypervisor, the administrator can configure a completely random set of MAC addresses to be assigned to the virtual servers. If that administrator changes his/her MAC address sets from time to time, then then records for those MAC addresses become useless to anyone snooping.
Proxies and Tor do exactly what I’m suggesting by funneling your data traffic through multiple routing points which can make a packet sniffer like Wireshark almost useless if the sniffing isn’t done on the actual endpoint of your traffic. Since Tor traffic is deliberately obfuscated across multiple endpoint routers, it would take a good deal of time and effort to track the actual data endpoints down unless, like some idiots I’ve read about, you leave your Tor endpoint router unconfigured and unsecured.
I never once claimed that you are completely anonymous while on the Internet, but if you’re encrypting your traffic with SSL and using a proxy and/or Tor to obfuscate your ingress and egress points, trying to figure out what you’re actually viewing and doing on the web would require a Herculean effort that most government agencies won’t bother doing unless they’re gunning for you.
MAC addresses have nothing to do with the Internet routing of traffic. Every single time you connect to the Internet your connection has an IP address. Your ISP logs that connection. If a sniffer is listening to the traffic on that IP address then it doesn’t matter where the traffic comes from as it is going to you. All the mumbo-jumbo, like proxies, going on after your IP means nothing if a listener is listening to your IP address.