Dual-port 100GbE PCI-E 4.0 network cards are now under $1300

I spent a few years implementing 802.3 physical layer testing. At the conferences it was clear that things were written carefully to not cover implementation, but they went so far in the necessary details that there were only a handful of reasonably performant and economical solutions.

So yes, it's trivial to saturate a 10 Gbit/s link, assuming that the kernel and userland can keep up with the hardware.

Wifi 6E can do almost wigig/uwb speeds, near 7Gbit hypothetical.

A single modern NVMe drive does 56Gbit.

USB4 can do 40Gbit. It can connect direct computer to computer.

But indeed as others have said, even broadband connections are exceeding this speed now. USB exceeds it by a factor 40 and is on cheap laptops. Yet Ethernet remains so expensive.

People will compare browser benchmarks over milliseconds so why not file transfers over the home network?

In general terms, cynicism about the "need" may be right. Most home users in most use cases likely won't notice much by going to 10G.

But then there is the rest of us and the other use cases.

As for systems that can push this much data. Almost anything with a M.2 SSD will easily keep up.

So for a use case, backing up your zillions of photos to at least one other point of failure on your home network. May not be the best backup plan ever, but regular home users are not IT gurus and will do this.