| van Eyck Lotto Caravaggio Optics Focal lengths Oil paint No documentation Arnolfini portrait Talent Problems tracing Demonstrations Future discussions Summary
Adoption of technology
There are many cases where "superior" technology is not adopted, and there are innumerable failed corporations and startups, penurious inventors and frustrated investors to prove it. While the public may believe "If you build a better mousetrap, the public will buy it," the truth is rarely so simple. (Incidentally, scientists and artists are insulated from these messy but crucial problems of adoption of technology.)
There are many reasons why the "superior" concave mirror (if indeed it was "superior") might not have caught on or been adopted by early Renaissance painters:
What these considerations actually imply is that "superior" technology must be judged on a broad range of cultural, economic, political and legal criteria -- criteria the theory's proponents have not considered adquately. It is very easy to counter the above points in theory, or in an ad-hoc way, but in practice they can arise in innumerable unexpected ways and can be amazingly frustrating.
Summary: Even if it could be shown that in theory the use of optical elements for painting was "superior" to "eyeballing," there are numerous hurdles to the dissemination and adoption of such technology.