Certainly will agree that the older Brownline tracks were poorly designed, and often resulted in seat separation.
Recall years ago in a DC-6 sitting down in a double and having the whole assembly wobble sideways. In the early 707's, the economy seats were also poorly designed, and tended to separate from the tracks, especially if three hefty folks moved the same way...at the same time, sideways. Perhaps it was the case of...if the tracks/mountings are redesigned, the inherent seat frame shortcomings became apparent.
Have noticed that in corporate jets, the seats do seem to be more firmly attached, especially in the JetStar, an old design, to be sure.