Yes, you would be very wrong.
Almost all TV manufacturers are going to 4K, but the technology used to create an image hasn't changed that much. That means, that a cheap LCD display isn't going to touch what the last model Pioneer plasma TVs looked like from over a decade ago. About the only technology competing with that level of image quality is the OLED displays. Guess what? They aren't cheap.
Full array LED lighting displays (FALD) also cost more than the cheapest LCDs and they are very good looking, but they aren't the cheapest.
As it turns out, time and time again, it costs more to get the better image quality, and most people would happily put their 10 year old Pioneer Kuro against almost anything on the market today.
It goes back to the source. A high quality source will yield a high quality image, and that's where cheaper 4K displays get a bit of an advantage. Just because they support that higher quality source from the start. But, it won't fix their black levels, motion detail, or shadow detail. Those three things matter a great deal more than resolution.