I would compare it to using the same compressor as DPS but feeding its level detection part with the same eq’ed signal as the Bongiovi AGC, therefor generating exactly the same gain reduction, but applying the gr to the original (un-eq’ed) signal then.
My (likely wrong) understanding is that this would be simpler and faster. So I thought that the Bongiovi AGC may achieves some completely different result/effect/sound. Also sidechains were invented long before Tony was born, so he would probably have used them if they could deliver what he wanted.
But from your answer I guess there are only minor technical differences.