With what feels like weekly posts about someone being shocked their smart TV is showing them ads, I'm surprised you looked for gigabit for your TV.

I've had a smart TV for over 5 years and never connected it to the Internet.

It is futile to expect the TV to be smart and support all sorts of apps and hardware only to be abandoned by the manufacturer years down the line. The only correct way to buy a TV imho is to hunt for a dumb but excellent display properties and get a streaming device such as Google TV Streamer, Apple TV or DIY x86 HTPC.

Unfortunately we're the weird ones for wanting to stream >100mbps content.

My 2020 LG CX has a USB 2.0 port and I get ~300mbps with a gigabit adapter, if the TV you ended up with has a USB port it's worth a try.

TVs are made with BOM of like 10$ for the SoC, so it's the cheapest crap available.

Then again - none of the streaming services are streaming at anything remotely close to 100Mbps so I doubt they consider it necessary to upgrade to GbE.