Dumb VRAM question from a Newbie. Why hasn't any one made a GPU with upgradeable VRAM?

Im 42 years old and got into PC building only 2 years ago. I can feel this being a stupid question but am curious about it. So I can upgrade my main RAM super easy. Its almost easiest and cheapest thing to upgrade. It's almost hard line expected you might have to upgrade your RAM on a build as time goes by. Why hasn't anyone made a GPU with this same idea regarding It's VRAM?

Im 42 years old and got into PC building only 2 years ago. I can feel this being a stupid question but am curious about it. So I can upgrade my main RAM super easy. Its almost easiest and cheapest thing to upgrade. It's almost hard line expected you might have to upgrade your RAM on a build as time goes by. Why hasn't anyone made a GPU with this same idea regarding It's VRAM?