Retailing parts is a different business than manufacturing and supporting kits, and we have found that it is better for us to focus on our core proficiency. The parts that are included in the kit have been chosen based upon 20 years of experience doing this stuff. Any talk about "designing to a price point" is going down a slippery slope.
We went thru this deal with attenuators when we developed the BeePre. We started with the stock pots, tried Alps Blue, PECs, S&B TVCs, Goldpoints, and probably a few other very highly regarded attenuators I don't recall. They were somewhat better than the stock pot, but when it came down to it we had to design our own attenuator to get something significantly better sounding than stock. Hence we sell the Bee Quiet kit. If you want to hear a Crack sound significantly better put a Submissive in front of it wth very short interconnects and replace the stock pot with 100K grid loading resistors.
Along these lines I spend a fair amount of time trying to explain to people that a stock Mainline is going to sound better than throwing $1500 worth of parts at a Crack, not because it has more expensive parts - which it does- but primarily because the circuit just plain sounds better.