It’s not so much that stock tires wear too fast (though, on average, they might). Mine, for instance, were too slippery for my taste. It’s more that stock tires tend not to be the tires for you. Between people like Munch, who want durability, and people like me, who want grippety grip grip grip, and between people like Miami Matt, who want traction in the wet, and people like California Cal, who want dry performance, tire manufacturers can’t possibly fit a stock tire that makes everybody happy. So they pick something in the middle. And that inevitably pleases no one.
I wouldn’t be surprised at all if, as Munch was suggesting (and he would know), there is a plot to fit new vehicles with fast-wearing tires. All the same, that’s not the issue for everybody.
I think SCR’s advice is great: you already have the stock tires. Ride ’em. This will let you get a feel for the bike without wasting miles on a fancy schmancy replacement tire. Many miles spent on the stock tires will give you a better idea of what you’d WANT in a replacement. When you hit the wear bars, grab a new set!