Dude, I'm not a network technician but I've been putting computers together since the late 80s and have been running Linux OSs as my desktop OS for over a decade now...
And I couldn't set up the network you described without some serious googling.
How are we supposed to expect normal people to do it? Do routers come with VLAN set up out of the box, jailed so that it doesn't send data out of your network? Somehow I doubt it.
Normal people are screwed, until routers are set up to manage IoT networks by default.
And let's be real: Normal people aren't going to buy a separate access point if their router has Wifi built in.