Yes, you are so right but not everyone has that luxury to find the perfect speaker with the perfect impedance match, and for some, the perfect speaker is an electrostatic, or some sort of Planer, in which case normal amps have difficulties with, far less an OTL.
This is what this amp was designed to do, to take whatever can be thrown at it, an still give you what you hear with the perfect impedance speaker.
So using your analogy, as long as all your bolts are 10mm, then all you need is one tool but some people rather larger bolts, or some smaller ones and a more versatile tool is needed.
You're all set, you have found your Nirvana but what about the guys that have those Spendors, Quads or speaker like these, they deserve their Nirvana as well :)
This is what this amp was designed to do, to take whatever can be thrown at it, an still give you what you hear with the perfect impedance speaker.
So using your analogy, as long as all your bolts are 10mm, then all you need is one tool but some people rather larger bolts, or some smaller ones and a more versatile tool is needed.
You're all set, you have found your Nirvana but what about the guys that have those Spendors, Quads or speaker like these, they deserve their Nirvana as well :)