OH .....OK.
This is all new to me. So the flash unit Does Not see the camera the same way.....hot-shoe compared to using the PC Jack.
Interesting
Not quite.
Some hot shoes have additional contacts, and allow the exchange of additional information between the flash and the camera. This additional functionality has become more and more common as additional automation has become common on cameras. In the case of the Canon A-1 or AE1-P that you referenced at the beginning of your thread, those cameras did offer additional functionality when used with certain Canon or Canon compatible flashes either installed on the camera hot shoe or connected via a proprietary cable.
However, the basic synchronization of the camera shutter and the flash is accomplished essentially in the same way, whether you use a PC contact or a (simple) hot shoe.
Not surprisingly, the connection at the camera end will depend on what the camera offers by way of a connection, and the connection at the flash end will depend on what the flash offers by way of a connection.
The suggestion to use inexpensive radio triggers is probably a good one. I'm not sure why M Carter has trouble with his RB's because my older IR triggers work fine with mine.
Another good option can be having a low powered flash on the camera, and optical slave triggers on your off camera flashes. This only works, however, if you are working where others are not using flashes.