I am fascinated by this. I wonder where your info comes from. I have always believed that Royals were the best typewriters ever made, but I didn't know there were others who agreed with me.
I still have a Royal portable from the 1930s that I've owned for decades. And I still use it for all my correspondence. (There are some advantages to sending someone a letter written on an old typewriter. If it's a personal letter, the handmade quality of it is a homey touch. And if it's business, it scares the recipient, because they know right away that you're a crackpot, and therefore possibly dangerous.)
But as far as I know, they're not all that valuable. I collect old typewriters, most of which are not worth much. The last time I checked on ebay, a Royal portable like the one I use, in good condition, costs about thirty or forty dollars.