There are also inherent differences in color response, clarity/sharpness, screen uniformity, "speed", the amount of blur during motion, and a whole host of other performance details that can and will be different from model to model... and those differences won't be anything calibration can improve. Even power supply design/capacity can affect image quality and you know when you spend $500 less on a TV that you're going to get "less" of everything... the power supply will have shortcuts or completely missing elements, features will be cut, the number of controls available for calibration are often cut from lower-cost models. Even things like the coating on the panel will be different as you move down the model range and that can make quite a lot of difference... it can make models with the better coatings (on the more expensive models) have better looking images that are less affected by reflections from light in the room. The quality of the coating on the screen can even improve the perceived black level the panel can achieve.
Typically what you see in lower-cost TV models is the same thing you see in lower-cost AVRs... the same circuit boards are used, but there will be empty spaces in the lower cost models where components supporting the "removed" features were not installed. So you can pay less, but you really do get less. The thing is whether the extra cost of the higher-end models is really worth the extra expense or not... that's something each person has to figure out for their own situation. Even then... there may be 4 models priced between, say, $1800 and $2800 and they might ALL have the same image quality, but different features (internet apps, streaming services, etc.), different styling, etc. It's damn near impossible for a consumer to figure out whether paying for the next model up the line includes better image quality or not. Many manufacturers have different "series" of TVs that span different price ranges. It's a fairly safe bet that each series up the line will have better image quality. But within each series if there are 3 different 50" models, those may or may not have differing image quality. Unless you can find a place that reviews TVs (and actually knows what they are talking about... somewhat rare) and they look at ALL the models in a manufacturer's line and evaluate image quality for each, it will be pretty impossible to figure it out on your own.