Generally, yes, if something is more expensive you can and should expect better quality.
My experience though with makeup brushes is that it’s not quite that clear cut.
I have brushes from a range of companies: MAC, Sonia Kashuk, Sigma, CVS no name brand, E.L.F and NYX.
I find they pretty much all do what they are intended to do. I purchase brushes based on the size and shape of the head with a specific purpose in mind.
Interestingly I recently purchased a duo fibre F50 brush from Sigma and a flat top B 07 NYX for the purpose of an airbrushed blush application. When I got them though I realized the Sigma had a much more compacted feel while the NYX was definitely sparser. Initially I was bummed out because I thought the NYX would serve no purpose. But I actually use it now to buff my liquid foundation once I put it on. I find it’s touch is light enough that it doesn’t cause any marks but the hairs have enough strength to give the foundation a flawless finish. The other one I use as a blush brush.
A big issue people are concerned with regarding brushes is shedding. I actually find that my MAC brush sheds a bit more than my others. But not too bad and they really are all great.
So see a brush you think will work for you but don’t want to spend that much? Try to find a similar style in a cheaper brand, even try 2 different ones and I am pretty sure you won’t be disappointed!