> guess the smart features don't add a huge amount to the purchase price

They reduce it, because having one do-it-all device increases units/SKU and decreases the contribution of fixed costs to the minimum unit cost needed to break even, and competition prevents charging excessive premiums across most commodity models.

I think that’s called a computer monitor

I know why you're getting down voted, but you're not exactly wrong. There used to be TVs and video monitors, and then there were computer monitors. They were all CRTs. The computer monitors were way more expensive than TVs partly due to being progressive scan vs interlaced. Televisions had low resolution and included things like speakers and tuners. Video monitors could be had with much higher resolution for post/broadcast facilities even though they were still interlaced.

It wasn't until everything went flat screen where "TVs", computer monitors, video monitors became so interchangeable. However, there's really not many 72" computer monitors to fill up the space in my living room.

For a while, computer monitors were limited by the HDTV specs, but a computer monitor usually has better specs - often resolution, refresh rate, display lag, connectivity options, etc.