Yeah, it's definitely true in mainstream products, but once you get into niche stuff there's a few different elements that come into play. Like yeah you do actually, measurably get more for what you pay, each brand just has incremental units with X and Y functionality added as you go along. But there's also an element of brand recognition and are you getting the top name in the business that can just price whatever they want, or are you going for the underdog that overdelivers for a lower price, but it may break on you or miss some of the shine.
Personally, I'm more likely to go for the higher/highest model, to squeeze the most functionality out of my purchase, but I'm also more willing to give the underdogs a shot and save big that way instead.