The story says the the cards and cash were tangled in a bush - not in a bag or anything, and the shirt was not where the other stuff was, but in the vicinity. On the news earlier today, they (investigators/sheriff, etc.) said that this discovery would be in line with a crash site spread out over a large area.
I don't think he wanted to disappear - no signs pointed to anything like that.
It's hard to believe that even with access to every technology he could possibly need, he ended up dying like this.
I sincerely hope he didn't survive the initial crash, only to die as he hiked in the desert, looking for assistance. That does seem like a possibility with these items found apparently without a crashed plane nearby.