Just my 2 cents here. In the case of a cathode bias amp, a small company (like myself) would use a heat sink wire-wound resistor and mount it to metal, or use thermal compound underneath it and mount it on the side of the chassis. Then a 200-500 mA fuse on the primary of the output transformer will also save the resistor from blowing in the case of tube failure. Without thinking of the 2-3 times markup that commercial companies have to build into the price to sell to audio dealers, you can spend more into failure-proofing components as a small business.
Boutique/custom vs production tube linestages
There are many boutique / small hand made tube audio companies (ie. Aric audio, supratek, Tube audio lab etc). Have you ever compared one of these devices to production gear (ARC, VAC, VTL, Atmasphere etc). And if so what were your findings? I suppose the idea with these more hand crafted creations is higher value but I am curious about your personal experiences.