Street side tire failure

[Kidkraz]

I've had my TM for just about 5 years now and have been wondering if I need to replace my tires. I just returned from an awesome trip to Yellowstone and the Grand Tetons with those original tires. I wrestled with replacing them but didn't. I did inspect them and aired them up properly for the long trip.
I was about 26 miles north of Wells NV when it failed. I have to say as badly damaged as this tire was, I had very little; almost no damage to my rig.
I replaced my toilet with a cassette toilet and have no toilet drain line that could get damaged. I do have the Enduro Caravan mover motors installed, but only an end cap is missing. The tire as you can see in the pictures is pretty bad. There are some tire gratings I have to clean off the bathroom area wall, but that's it. I just did a good inspection and will ask a friend to do a double check just to make sure I didn't miss something.
When it failed I was a couple hundred feet from an empty lot off the side of Highway 93. The sun was still up, my friend and I had some minor struggle getting the trailer up high enough to pull of the damaged tire and get the new one on. We had to open the trailer, cause the socket to remove the lug nuts was in the tool kit sitting in the cabinet under the oven. We started just before 6PM and was done getting back on the road at 7:10. We stopped at the first gas station in Wells, checked and service the replacement tire since it has been sitting underneath to TM since it was built. Retorqued the lug nuts and drive the remaining miles home.
I do have some questions that are of concern to me. When we went to break the lug nuts free the wheel was in the air and was spinning. I thought to apply the truck brakes which I would think would stop that wheel from spinning, but it didn't. I tried to apply the brake using the test switches on my truck brake controller and the wheel still spun. This makes me question weather my left side trailer brake is operating properly or my brake controller is operating incorrectly.