You or your gunsmith have Weatherby and Winchester reversed. Weatherby uses the same bolt nose design as Remington....the only reason I have my Remington is because all the custom work was already done to it (blue printing, trueing, rebarrel, timney elite, MDT chassis). Otherwise I would own purely Weatherby. There is a .300wby and a 6.5-300 both in accuguards that I have considered purchasing.
The most fancy platform (Vanguard)? No, but they are reliable. You’re right though, there doesn’t seem to be nearly as much after market support as there is for Remington, Savage, etc.
One advantage I do believe Remington has over Weatherby is their bolt design. My gunsmith explained the differences between the two, I don’t recall the specifics. In short, he said that you are safer behind a Remington than you are a Weatherby if you experience a case failure. It boiled down to the differences of a safety breach (remington) versus a cone breach (weatherby). The safety breach has more obstacles for hot gas and molten brass to get by whereas a cone breach has minimal obstacles, allowing for hot gas and molten brass to reach the shooters face easier. Weatherby has vented the sides of their bolts to aide in gas redirect if this were to ever happen.
But if you’re a safe reloader who doesn’t push limits, or you shoot factory ammunition, what’s the difference? Shoot what you like better.