The Cap Code system used by Motorola did include most commonly used tones from other manufacturers but not all. It was restricted to 16 groups of 16 tones as well as a few other restrictions that kept the total amount of tones down. Plus, once the system was in place it would be difficult to add new tones to older consoles.
In the old days tones were programmed into radios and consoles with mechanical devices like reeds and filters, so manufacturers tended to use a finite set of tones to keep parts inventories down and for other reasons. This had the effect of keeping individual tone sets within specific groups, so that Plectron "A" tones were almost always married to a Plectron "B" tone and so on.
Use of custom tones, either not members of the manufacturer's groups or not on lists of others were rare. Mixing of tones from Motorola and Federal or others was also rare.
Newer radios and consoles are programmable and not restricted to what tones they used or specific sets available, you just put in the number and off you go. While many installations still tend to use tones from groups in order to accommodate older equipment that may stil be in use or since there is no reason to go and change existing tones, many users are no longer bound to specific groups or tones. These users can now use any tone that they want.