[foobiekr]

"What happens when multiple devices in your /8 want to listen on port 80 and 443 on the public address?"

This is a feature not a flaw. The average person doesn't have anything acting as a server, and that's a good thing, because the only servers they'd have would be embedded garbage in poorly maintained or completely abandoned IOT devices with incompetent code that should not be publicly exposed, ever, in anything but a call out model.

[megous]

Firewall is a feature. Forced NAT that noone in the above described situation wants is just a flaw. And the other solution where you're forced to buy a fucking "public" number out of a grossly insufficient pool of those for $5/month for each of the NATted machines and your router, is a crime against humanity.

[nomel]

I'm naive with network security, so this is a honest question looking for a practical honest answer: Would my grandma's computer, with its old version of windows, be more or less safe with a NAT without DMZ configured?

[avianlyric]

Using a normal ISP issued router, wouldn’t make a lick of difference if it was IPv4 with a NAT or IPv6 without a NAT. They’re all configured out-of-the-box with a default deny firewall. I’m not actually aware of any residential grade router that doesn’t come configured like this.

Of course if the router is misconfigured, then all bets are off. But that’s true regardless of IPv4 vs IPv6, because people will just compromise your router first and use that as a launch pad for the rest of your network. Just like to do today with plenty of old residential routers.