Good question.
The first Suunto wireless AIs were analog, not digital, and had many problems. They came out around 2004, I think, and this is what gave wireless AI a bad name. Suunto finally became digital, around 2016, I think. They still require pairing with the dive computer, and this can be lost. In contrast, the PPS/Aqualung MH8A series came out after 1995 (the date of the FCC ID for the transmitter) and was definitely in operation in computers in the early 2000's.
Battery technology evolved, so the early MH8A units used 3x #357 button cells. The modern units use CR2 batteries. Several dive computer manufacturers got on the MH8A bandwagon, so you saw wireless AI using the MH8A from Oceanic, Aeris, TUSA, AquaLung, Sherwood, Hollis, Apeks, Shearwater.
As far as I know, all transmitters being produced today by all the manufacturers use digital transmissions (some over RF some over acoustic carriers), and all are reliable. These are the second generation systems. The early Suuntos were first generation, and terrible, really.
One reason for the reliability of the PPS system is that it does not require "pairing;" the transmitter just transmits, with an ID encoded, and the receiver (the dive computer) is told what that ID is. The computer hears all transmissions within range, but only fully decodes the one to which it is serial-number matched. There is no "pairing," in the sense of back-and-forth transmissions like Bluetooth. The dive computer is a dumb radio receiver, tuned to a particular station (transmitter).