Back in the old days, we relied upon the room or the hall to produce natural reverb, the tricky thing was that invariably, when you did a sound check, the room/hall was empty, so if you were using any form of delay, or as it was known then "Echo" , which was "usually" provided by either a Klemt Echolette, or the more commonly seen "Watkins Copicat", that would be sitting behind your amp and cabs and there would be a "Roadie" stationed there to adjust things once the venue had filled. This is actually why you rarely saw a band doing anything too complicated during the first number, as this was the time that the band/ the soundman and the roadies were getting the feel of the venue. The advent of the digital delays made life far easier as you were able to make adjustments on the fly and not relying on a third party to get you near enough.
Personally, I have always preferred the sound of our old Tape Echoes, much warmer and organic to my ears. The best of the best was of course The Roland Space Echo, which allowed you to do some pretty insane things!!