I've not been following this thread because its title referred to Jeeps and I didn't figure it would be relevant to me, not ever having owned one. But this a.m. curiosity got me and I checked it out. It is relevant to me after-all, at least as a fellow highway user.
I too have always figured a Jeep would have a stout frame given its reputation for off-roading. A couple of relatives had Liberty's at one time or another, and they did seem a bit less attuned to much 4X4 activity as compared to a Wrangler, but then so does my Explorer Limited. I've noted my Roadmaster brackets, however, are fastened to some pretty thick frame members under the Explorer, at least compared to what's in your photos.
I would think that beyond alerting others here about the issue, Chrysler/Jeep should be sent the information and pix, and perhaps the NTHB. If Jeep is going to continue touting its vehicles as tough and tow-able 4-down, perhaps they need to consider a design change. Admittedly yours is an older model, but I'm not sure any manufacturer is building new ones with any thicker and less brittle steel these days.
Joel