I don't wish to start a debate here, so I'll just make a few observations and try to keep it neutral.
I have no access to the number of wooden ship kits sold every year. All I know is that personally I buy about 0.25 or so, yearly. And I do build them.
I probably buy about three or four plastic ship kits every year, and maybe one is a sailing ship.
As far as the subject matter, my plastic ship kits are top-down. In other words the more complex the better. The most recent plastic sailing ship I've bought is the Pourquois Pas? which is a fairly complex subject. A Fletcher, a couple of carriers and a Lindberg Q ship (two actually) round out the lot.
My wooden ship purchase this year was a Model Shipways Dapper Tom, and I was given a MS Virginia Privateer (Santa paid money). Both a little complicated, but both also very buildable.
So at least for consumer Morrison; there's no real overlap between wood and plastic kits. I could never imagine taking on a wood Constitution kit, as I would never get it built and the sheer tedium of making so many assemblies would wear me out. Likewise a plastic sloop or schooner, while it has some attraction, just begs to be built from wood, cordage, etc.
And I am going to guess with a pretty great deal of certainty that almost no big wood sailing ship kit, esp. from Europe, ever gets finished. I do read a fair number of wood model websites, something like a twenty gun frigate is about the upper limit .
I guess that my observation is the cost of kitting any plastic ship is pretty great, and needs a lot of units to sell. The first X number of thousand kits pay for the molds, the next for the box etc. So big complicated kits are a realistic choice. But how many of us ever will build more than one Royal Sovereign?
As for simple subjects, looking in the Privateer box, there's mostly the proverbial pile of strips of wood, some laser cut stuff and some Brittania castings. Nylon cordage (Ugghh!).
Not a very expensive product to produce, sold at a considerable sum retail (mine came from an estate sale), and probably profitable in small quantities. Yes Round 2 is selling those funny little plastic ships again, but they cost about 20-30 times what they did originally.