> Is there a private organization in need of 16 million addresses?

Plenty of mobile phone networks have well over 16 million subscribers, and they typically don't have enough public IPv4 addresses for everyone. This has led to really hacky stuff, like using DOD IP ranges as psuedo-private space, or re-using private IP addresses in different regions (which can't be fun to maintain.)

Some networks have fixed the problem by using NAT64 - forgoing IPv4 altogether internally, and translating to public v4 at the edge. (Works surprisingly well, T-Mobile US has been doing it for the better part of a decade.)

It's not about number of addresses available, it's about reflection of organization hierarchy in the octets. The 10.0.0.0/8 range is useful for breaking a distributed company's network up so each major office gets a 10.x.0.0/16, and each department a 10.x.y.0/24.

This is why 192.168.0.0/16 is often used for services like libvirtd, kubernetes and docker. And the use of the range by those services makes it even more unwieldy to try and put some other LAN in there.

You can work around these considerations if you want, but many people won't. When you're the network engineer responsible for designing a company's networks, you'll be wanting to keep things simple and robust. When you're called in at 3am on a Sunday because the network is down, you better hope your ability to recover doesn't require making a bunch of subnet calculations because you decided to try and use the pool of available IP addresses efficiently.