More like :

2008: profits from TV sales are declining rapidly. Manufacturers are panicking.

2018: TV manufacturers partnered with some shady organization that pays them big bucks to install spyware into their Smart TVs.

2008: Manufacturer finds a defect in the firmware code that causes excessive processor usage, thus causing the internal electronics to fail earlier than anticipated. No fix available.

2018: defect in firmware found. New version deployed to internet connected devices and lifespan extended.

Both of those are made up scenarios, but I would argue that there are legitimate reasons for devices to be connected to the internet. Along with a bunch of terrible reasons, of course.

My 2008 TV did get firmware updates over cable TV.

Yeah, sometimes those might actually make things go smoother, but generally it's security updates, which you almost certainly won't need without internet connection.

In my case, it fixed a random black screen Vizio e48u-d0 with an intel NUC pushing 4k 29hz.

If you ever read some av forums, you'll find that modern TVs are about as reliable as modern computers, i.e. it's amazing they even turn on when requested. Features are DOA for new lines and need multiple updates to be useful, sometimes they're completely disabled and only get enabled after a year, e.g. Dolby Vision on 2017s Sonys.