Because those A/V transmitters used the same 2.4GHz ISM band as WiFi at the time, there was actually no regulatory protection against this interference - from a regulatory perspective it's just a normal and expected part of using an ISM band where there is no protection. The increasing popularity of WiFi started to really surface the problems in this area, similar issues are seen in 900MHz far less often because it's mostly used with low-power, low-duty-cycle devices.... the same as was intended for 2.4GHz before widespread consumer WiFi.

In GTA 4 (set in the early 2000s or so) you hear that on your car stereo before your phone rings. I always loved that detail.

Unfortunately both examples are misleading:

Unlicensed equipment in the ISM WiFi band are operating under Part 15 (in USA) so must accept any interference.

And the phone interference to a stereo is caused by cheap and nasty design of the stereo. The phone itself cannot be blamed, and there's nothing which can be done to the phone to fix the interference (other than switching it off). Again the stereo is probably operating under Part 15, so must accept any interference.

The effect of GSM phones on analog audio equipment was actually an oversight in defining the standard. Fully compliant equipment had that effect.

Some years back when I had some small involvement in new EU regulations that case was actually given as an example of how, even after many reviews, some forms of harmful interference can only become apparent after a technology is already widely deployed.