Actually many of our modern instruments have only just arrived where they are, and it's not hard to argue that we're merely another point along the time-line, and that they'll continue to evolve.
I've been thinking about it and a couple of things occur to me.
One is that quite a nice aspect of recorder playing is that it's easily possible to experiment with so many points along the journey. I know costs vary a lot, but it's easy enough to get hold of such varied instruments as
- a reproduction of either of the Tartu or Dordrecht instruments
- accurate reproductions of mediaeval and renaissance instruments in assorted pitches
- general-ish baroque instruments as well as specific reproductions
- simple modern designs (I'm thinking eg Moeck Flauto Rondo type instruments)
- something a bit different like an Adri's Dream
- something very modern like a Mollenhauer Helder
and no doubt other variations I haven't thought of.
The other thing I think, which is a bit off-the-cuff and could very well be wrong, is that musicians must have been a more adventurous lot once upon a time. Based purely on anecdotal evidence, and the impression I've been given by the (very) few professional musicians of my acquaintance, they seem quite conservative and resistant to change nowadays. When I played saxophone, reeds were just the bane of my life, always breaking, never quite right. I think modern plastic ones are great, but the reed players I know generally hate them, and think there's really something not quite right about a reed you don't have to pamper. Would so much change have taken place in the eighteenth century if people then had been as resistant to change as they are now? Or maybe the changes crept in more gradually than seems to be the case with hindsight.
BTW in case anyone has not noticed, there is some great free music around at the moment. NY Metropolitan Opera and Vienna State Opera are both streaming an opera a day - today's offerings are Eugene Onegin and Siegfried respectively, and the Berlin Philharmonic is offering a free month of full access to it's digital archive. We enjoyed a brilliant performance of Mahler's 2nd Symphony last night, suitably uplifting for the times. There are probably other things on offer too.