Podunkfla wrote:I'm wondering why you can't get sealed roller bearings like on the front end of my Chevy S-10 Tahoe? I finally had to replace one at 267,000 miles! Would sure make sense for a trailer that sits most of it's life.

You can. The current Al-Ko axle currently used in Europe has sealed bearings standard, Dexter offers them in some hub sizes as Nev-R-Lube, and U-Haul included them in their rental travel trailers two decades ago.
I agree that in this century sealed bearings are the way to go. I've never had to replace one, but I have only made it to 354,000 km (a little short of that Chevy) on a vehicle; I don't know how much further I would need to go to wear out the bearings.
I'm sure that small trailer axles do not have sealed bearings simply because they are cheap.