right on the 17th century -my point was that the finest of work was being done before then. At least from what I've read/heard, and i'll admit not taking an interest to a level of being able to say anything accurate other than my assumption was that fine work occurred first, and the supposition is that a mature planemaking market (instead of a cabinetmaker just making their tools, inheriting, whatever it may have been) is a younger concept than a mature cabinetmaking trade.
work older than the late 1700s isn't common in the united states unless, for example, a well-to-do family here has gotten a habit of importing 16th century french stuff - thus, it's more or less hypothetical to me except that my experience in making tools is that many things folks would consider backwards or antiquated actually make better tools (for example, an open mortise simple drawer grooving plane with a fixed fence and a matched runner - to the iron - will make a far easier-to-use plane than a plane with fixtures and a skate). The "penalty" in time for each of these specialized tools (which are lifetime tools, even though not visually impressive) is usually an hour or two at the most, made entirely by hand including the iron. People willing to glue plywood together can have the title of fastest to make - even I have my limits taste-wise.