I'm not sure that's a fair blanket statement to make. I don't think I've bought any new devices with only 1gig ports in quite some time. My work laptop has 2.5GbE, my 5 year old desktop has 2.5GbE, my NAS has 10GbE, etc. 2.5GbE switches have also gotten quite cheap.
My WiFi 6 router only has gigabit LAN ports, but that's because I didn't personally need to go any higher than that. Faster options were available at the time I bought it.
My point is that consumer electronics are generally available with >1GbE if the application suits it. If you only buy the cheaper models then 1GbE is more common. There are plenty of applications where even 1GbE is overkill and spending any more money on a faster link would be throwing away money.
Still though, I think this is just a case of Apple making them heavier purely for a premium feel.