And so on and so on. If you want to be tracked, you can be tracked, regardless of a mac address, or the hoops a user jump through to create the illusion of privacy. I can think of lots of unconventional ways to track a naive user.

Still within a subnet. If you connect to an internet cafe Wifi, you should be more worried about your dns traffic for identifying you.

How is this a problem when the hardware address is dumped once packets are out onto the web? Are you worried your router knows it’s you? Outside your subnet, on the internet, your Mac address is not part of the packet.