> Our company is often asked at expos if we supply 2 wire ethernet switches (e.g. Single Pair Ethernet SPE[1]) but the reality is there's little demand

This reminds me of a funny conversation I had in a small town stationers when looking for an item.

‘No, we don’t stock it. People keep asking, and I keep having to explain that there is no demand.’

Though this wasn’t for an obscure Ethernet variant.