Was at my buddy's house last night for a bbq. He has been in the collision repair business for 35 + years. His job is to cut off all of the twisted metal and weld in the replacement pieces. He has to make sure it is structurally sound and all the panels line up, then it gets sent to the finishing guys. I guarantee he has welded on more cars in a year than Tony has his entire life.
Anyway, I asked him what he thought about this and he laughed. He said the only reason the factory didn't tie the subframes together was to save money.
Your friend maybe not be entirely familiar with old Mopar unibodies. IMO, the main reason was space/lack of floor height/ road clearance. I can't see using the rockers/door sills as compromised frame replacements saved much, if any money.
A unibody is a unibody. Doesn't really matter what badge is on the grill, for the most part. Yes, there will be different approaches to the engineering, but the bottom line is that if it will save money and they can get by without it, an OEM will leave out something.
You are kidding about the ground clearance, right? It's not like Mopar was building lowriders.
No, I am not kidding, typical mopar owners back in the day, would be rather put off by having a FC protruding into the floor, and if a robust FC (ie Deep) was under the floor , it would have made the car a good candidate for getting high centered over a steep bump. A frame connector solution would have been cheaper then the solution we were given. There are a lot of pieces, welds, fitments, etc that a single robust FC per side would have replaced.
