I think many members here do not realize the cost of decent components before you even get to think about building and finishing the cabinets.
The performance that you can get from well designed and crafted drivers compared to much cheaper ones, is staggering and not in the least bit trivial.
A driver like this is expensive and easily justifies its cost.
So that is $468.00 a pop. If you are going to produce a speaker that really delivers the goods then you will need at least four for a pair of speakers. So that is $18472.00 before you have bought four mids and two tweeters of commensurate quality. Yes, it really will take four mids to produce a speakers able to produce concert levels without distress. The quality crossover parts will run at least $200 or more for the pair before you have built the board or boards.
So you can see, that if you are producing a really fine speaker your production costs are going to be high.
However the performance difference from well designed speakers built from quality components like that compared to drivers costing $50.00 to $150.00 each is not a marginal difference but a chasm between the two.
Really good high spl. speakers will always be expensive formidable products, if the design and R & D is of the required standard also.