And there are a few other things that play a role, like the fact that;
The total structure of the company worldwide (divisions, sub division etc) has changed the last period.
There are new lines like the PHX and Absolute models that require the same quillity check as you`re set.
And, The Osaka plant isnt a huge factory as you would expect. Its still a handmade product factory. There are only a few (though still men controlled) machinery like the Air Seal Shell machine and a
Lackering machine.
Everything else is hand put together, painted and checked with the help of small machinery like drills, paint brushes etc.
Often one part of the production is done by one employee who those this his and hers whole working life (and thats long and always with pleasure and commitmend)
Than you also have to deal with orders that are not standard like your`se, that will need to go trough the quallity check, and the paperwork that comes with it.
At the end I`m not suprized that it takes a few months waiting on a quality checked customized product.
Its a little strange to mension players like Weckl getting a royal treatment. They travel worldwide, work there asses off with recordings, playing live and other things. So for them drums are working tools. And even tey have to wait for building, checks and paperwork.
And lets not forget that they offer a huge input to the company to (wheter by advertising, clinics, signature lines or other) witch sometimes creates brand new or renewed products like the HipGigs, Groove Wedges, sub-Kicks, Hardware mods, snares and even complete kits.
But also in educational form like videos (Tony Vederosa's Dtx video, Weckl's video series and so on) clincs, appearances on tv shows, (drummer)festivals and summer camps like the Sonny Emory Drum Camp witch attracts drummers frim all over the world. And the "yeah Teddy C. plays that Birch Custom, im thinking of buying one after a closer look" thing (witch always happens)
So plenty reasons why a company offers something more/different to the ones that are a offering more than the players that don't or can't.