Even worse, in the only third party testing that was performed, by the University of Washington, they rated the original iteration of the Titan only up to 9800 ft. As far as I can tell, Oceangate never redesigned the sub after that, and still decided to take people to 13,000 ft.
Also, given that Rush would brag about how cheap the original hull was, I doubt they fully replaced it when they noticed cyclic fatigue in the sub later. To me it looks like they did some kind of shoddy repair. And that's the Titan everyone ended up with.
It has since been reported that Suleman Dawood was actually very excited about going on the sub, and had been previously disappointed when he couldn't go the first time the dive was scheduled because he was only 17, so his mother was going to go instead. That dive was cancelled, he turned 18, and you know the rest.