I've wondered that myself.
I also have a FE and one of the fender skirts has cracked at one of the screws. I'm going to pull it off and re-enforce with JB Weld, from the backside and I can then drill a new mounting hole in the JB Weld. I'm thinking of just going ahead and putting a gob at all the screw locations while it's off the trailer to fix the one screw hole. The caulking is nearly 4 years old and looking a little flat so this will fix 2 things at once since I will need to recaulk anyway.
I don't think the tires throwing mud or even water from the roadway up is a problem on a FE. My tires are 100% inside of the outside sidewalls and I'm pretty sure my plastic wheel trim is just for looks.
I've seen some trailers that just had chrome trim around the wheel well openings at the flat side of the trailer, no skirt. Did not look bad at all. I can't remember what brand it was (saw it last week while looking at RV dealer sites, so it was a new model). I thought about that as Plan B for my cracked screw issue, but then came up with the JB Weld idea.
Just the 2 of us in a...
2015 Freedom Express 246RKS
2002 GMC Sierra 1500