I'm sure people said exactly this about IPv4 back in the days.
The original numbering plan for IP was that each network number became a /8. Which is how we miraculously ended up with 10/8, because network 10 was ARPANET itself, so 'flag day' left 10/8 vacant.
But back to the point at hand. IP itself is RFC 791, September 1981, nice and famous. The addition of classful networking because 255 network numbers wasn't going to last long, was RFC 790.
The first workaround for IP exhaustion was published before IP. It's been a Known Issue since day negative-one.
That subnet is large enough to then assign an IP address to every individual atom in that grain of sand.
For comparison, if we wanted to assign every living person on Earth a grain of sand, we would only need a few cubic feet of it (less than 1 cubic meter).
As parent said, I'm sure people made the exact same argument about IPv4 back in the day, but comparing it to something else.
And when IPv16 finally appears in the future, people will yet again make exactly the same argument.
You're ignoring the sheer scale of this question. We don't have enough raw materials on this planet, or likely in the observable universe, to produce enough devices that would consume that many IPs.
We could colonize 1 billion planets.
Each of those planets could have 100 billion people.
Each of those 100 billion people could own 1 billion "things" that could be considered "networked devices".
Each of those "things" could consume 1 billion IPs.
We could have all that, and we would still have 70% of the IPv6 space left.
> The decision to put a 32-bit address space on there was the result of a year’s battle among a bunch of engineers who couldn’t make up their minds about 32, 128 or variable length. And after a year of fighting I said — I’m now at ARPA, I’m running the program, I’m paying for this stuff and using American tax dollars — and I wanted some progress because we didn’t know if this is going to work. So I said 32 bits, it is enough for an experiment, it is 4.3 billion terminations — even the defense department doesn’t need 4.3 billion of anything and it couldn’t afford to buy 4.3 billion edge devices to do a test anyway. So at the time I thought we were doing a experiment to prove the technology and that if it worked we’d have an opportunity to do a production version of it. Well — [laughter] — it just escaped! — it got out and people started to use it and then it became a commercial thing.
- https://www.youtube.com/watch?v=mZo69JQoLb8&t=816s
They were contemplating 128 bits addresses all the way back then, but settled on 32 bits as a mere proof of concept that got out of hand.
Of course we'd all be paperclips long before they need to worry about networking