It is also the least well supported of any speed (10gbps being the most well supported)

I would say norm for 20 years at least.

Sad, especially when Ryzen chips have dual 10G support in the silicon, but only enables in on some products in the name of product differentiation. Dual 10G cards are generally still pretty expensive, and motherboards with dual 10G are often several $100 more than the 1G version ... even when the 10G is supported by the CPU, like on the Xeon D series.

So basically people are still willing to pay more for 10G, and 2.5G is now the "free" upgrade. So my Comcast model, random Ryzen motherboard, and random SFF desktop all came with 2.5G. Sadly same on the Apple side, the Mac mini has an optional 10G, and you have to upgrade to the $$$$ Mac studio to get 10G by default.

The vast majority of existing wiring is cat5e which 2.5gb is the max speed

And there's even more pre-ethernet POTS wiring. But most of stuff built or renovated in the last 30 years has gotten fiber put in. Which is also much more power efficient than the faster ethernet standards over twised pair.

(Also your cat5e should do 10G for the most common short distances, it's not categorically different, just has looser signal integrity specs than Cat6. Just isn't guaranteed over the 100m max specified distance)

Nonsense. I've used 10GbE over CAT5 cables, plenty.

The upper limit for 10GbE over CAT5e is about 45m: https://www.universalnetworks.co.uk/10gbaset-can-this-be-run...

I expect that is sufficient for most residential installations.

Not sure I'd calls more than doubling "marginally faster".

I'd imagine the answer is cost & cooling. 10gbe is substantially more energy intensive than 1gbe.

You’ve gone from maybe a dual core processor and 8gb of ram, 500gb of mechanical storage and 512kbps internet w/ a gigabit mic to a 24core processor, up to 128gb of ram, SSDs, gigabit internet to see only a 2.5x speed increase in ethernet?

Edit: to be clear I don’t expect he same rate of growth due to the lack of use at speeds upwards of 10gbe for the average user, but over a 20 year span, 10gbe should be commodity hardware.