Robertson is a superior fastener design that never really took off in the USA. You see them at every hardware store in Canada. I suspect it's kind of an Edison vs. Tesla kind of story and in this case Phillips became the standard. Today you see hex drive and Torx drive, which are basically just variations of Robertson, which uses a tighter pressure fit to ensure the tool doesn't slip out under higher torque. Being moderately OCD, the appearance of a damaged fastener really bugs me!
I for one was impressed to see a lot of Robertson in use on Lance trailers. I have noticed as I have changed out certain components, like vents and fan, that the norm out there is still Phillips. I'm also not sure if I have seen Robertson at Ace Hardware, despite having all kinds of specialized fasteners.
In the USA they are frequently (incorrectly) referred to as "square drive". This is probably all rooted in some kind of trademarking/distribution/patent dispute.
So don't just replace your Robertson fasteners. Buy the proper tools and celebrate that what you have on your trailer is superior 