if it was out of alignment, you’d think the tire on the other side would be worn as well. I defintely wouldn’t hurt to check it though. Assuming your front axle is square, measure the distance between axles on both ends. You could also have a bent spindle or bent axle. When the tire looked skewed, did you back the boat up or turn a corner immediately before looking at it? The tires on my tandem turn all cockeyed when I’m making a sharp turn or backing up at an angle. Another possibility is that the camber could be off causing the tire to lean inward.
If it’s an older trailer, you’re also going to want to periodically check the shackles and other misc. hardware on your trailer for wear. When I replaced all that stuff on mine a couple years ago, I was lucky I still had axles under the trailer. The bolts were the shackles rode were worn about halfway through. The shackles in the same spot were almost completely worn through as well. Needless to say, I was quite alarmed when I saw that. You can’t see the wear unless you take it apart…