For example, my (modest) home LAN is five routers, a NAS/media server, a media player, two "smart TVs" and dozens of notebooks and phones connected via Wi-Fi.
What do you propose? Manage a firewall on each of those devices?
I suppose you mean setting up a firewall on the WAN link to block all incoming traffic? How is that different from a NAT? Merely a lack of 'masquerade' setting on the firewall rule? What's the benefit to me and why should I care?
Or do you propose some sort of hybrid scheme to intelligently block traffic while making all my countless devices pingable from the Internet? Not in this timeline, sorry.
NAT allows people to be very dumb about networking. Either you "open a port" or you don't.
It works very well as long somebody else is managing the network for you and you just ask for stuff to happen and then that somebody else has to actually make it work.
As for cloud, no idea what the benefit should be there.
