Keep in mind though, that once your Layer 2 is hijacked, a lot of attacks are possible before upper layer security kicks in - things like browser redirection and exploitation are very common these days

I agree. Highly assured systems of the past and recent academia built security on untrusted networks, storage, etc. Standards like Wifi are too broken to trust anyway. Best to depend on something at a higher level.

Note: WiFi security is useful for filtering out the riff raff for availability & performance reasons. :)

I was with you until "so that IP addresses finally can represent identity".

You don't mean actual (personal/account) identity, do you? IP addresses represent a location for delivery and they definitely identify a network interface, but that's the extent of goals for IP addressing. Courts have supported this view and I think that's a good thing. Sorry if I read too much into what you said. EDIT: spelling.