It's also the case with virtually everything, higher performance linearly increases price exponentially, you can get good functionality and performance from a $50 meter, but you can't get anything close to double the features and performance for $100. Let's say you drop $1000 on a nice 6.5 digit bench meter, well getting one more digit worth of accuracy is going to be double the price, at least, and getting that last 8th digit is double that price again, minimum.... but that's also about the limit you can get out of a benchtop instrument without really exotic measurement techniques in laboratory conditions.
The justification is if you need the performance, otherwise, you're just spending for your own interest or for a bit better build quality or whatever. Most people don't need a really fancy meter, but there is the occasional application that needs a very high precision meter, and the price reflects of the difficulty of making it and the much lower volume of sales.