Your lock example isnt perfect, it cant fight back.
In IT, you need both joined up offensive and defensive measures which includes self destruct if secrets need to be kept. That is at best a Check Mate.
Take a VPN, in nearly all instances I have encountered the only traffic is genuine traffic, there is no dummy traffic to muddy the waters from external Deep Packet Inspection.
Likewise routing can be used to isolate, I'll give you a real world example which you might be able to relate to.
You are travelling by car from A to B, and you can take a variety of routes to get there. Most modern cars now have built in sat nav, and all you know is when your target is leaving and they will be using the car manufacturers satnav. So you have a window (at the start of their journey) in which to manipulate the targets satnav by giving it fake traffic data to cause it to take a particular route. Ergo you have been able to isolate your target onto roads they wouldn't normally travel. Now that can be done nationally over the radio station network, or nearby using a transceiver SDR in a chase car.
What makes you think the internet is any difference? Business efficiency like JIT is a weakness as we see with the chip shortages and other problems caused by covid lockdowns. VPN companies are no different, they need to maximise profit so they dont add in fake traffic to hide their customers traffic, and by virtue of being able to choose from multiple VPN providers, users self isolate themselves into yet smaller groups. VPN providers should really organise and share networks to further muddy the waters from external entities.