Whats the difference between cheap and expensive modern TVs?

I feel like it used to be size, color, and clarity meant more expensive. Now I look at a 500$ 4k TV and a 2000$ 4k TV and I don’t know what the difference is. They can both be smart TVs, be the same size, and have a lot of same advertised features, but what are the subtle unspoken mysteries that justify a huge price gap?