Didn't have time to listen to the whole thing yet, but from what I gathered it's two things: the lower 64bits of the 128bit addresses doesn't count (due to privacy), and that carrier-grade NAT might go much further than what some people think.
If all you want to do is to watch YouTube and check out Instagram, and Google and Facebook have servers in a rack "nearby" (in the network sense) ala what Netflix does, then you don't need a globally unique IP to talk to them.
> If all you want to do is to watch YouTube and check out Instagram, and Google and Facebook have servers in a rack "nearby" (in the network sense) ala what Netflix does, then you don't need a globally unique IP to talk to them.
A "consume only" internet sounds like a second rate dystopia, doesn't it? (Where does the next YouTube/Instagram/Google/Facebook come from when the hurdle is they need to install lots of middle boxes to small, more siloed networks?) Not to mention the name "internet" itself comes from the global joining of a lot of individual networks. A re-balkanized "internet" with a lot of mostly disparate networks that don't really talk directly to one another hardly deserves the name "internet" at that point. (From that perspective CGNAT is an attempt to murder the internet from the inside.)
> the lower 64bits of the 128bit addresses doesn't count (due to privacy)
That's not how that works? For privacy a device is picking a 64-bit random number, sure, but that's still 64-bits of random numbers for a lot of devices to roll before collisions. It's not like it is just one device per lower 64-bits of address space. (Sure, maybe for "privacy" to avoid easy/obvious port scanning you superstitiously avoid "unlucky numbers" like ::1 or ::ffff:ffff:ffff:ffff, but that's still a lot more random numbers to roll than anything "the lower 64bits doesn't count" implies.)
(ETA: And of course, that assumes you are using privacy-focused SLAAC. There's still the power to micromanage a prefix with DHCPv6 and allocate every single one of those lower 64-bits if you really must.)
> For privacy a device is picking a 64-bit random number, sure, but that's still 64-bits of random numbers for a lot of devices to roll before collisions.
I don't have billions of devices in my home network, yet they eat 2^64 worth of addresses cause my ISP hands me a /64.
Which is fine. There are 330 million /64s available... per person on the planet. Your home network using one single /64 out of that isn't even a blip.
(Actually, if that's all you can get then it's not fine. Your ISP should be handing you, perhaps not by default but certainly on request, at least a /56 so you can have multiple networks.)
On a personal note, I used an ISP with CGNAT for a very short while, and it was despicable. It completely, utterly breaks any possibility of peer-to-peer stuff, in million little ways like UPnP being insufficient to make online gaming work as expected. It was just awful.
If we're going to talk about "need", then you don't even need a computer. You could walk over to the rack and watch the yougram on its management console.
But there are advantages to having a computer. Similarly, there are advantages to doing your networking right, and that means globally-unique IPs.
If all you want to do is to watch YouTube and check out Instagram, and Google and Facebook have servers in a rack "nearby" (in the network sense) ala what Netflix does, then you don't need a globally unique IP to talk to them.