Air Safety and the 5G Rollout? Poor Planning? Or Airline industry CYA?

The Union-Tribune reported this morning an Associated Press column that the mobile phone industry rejected the request from the airline industry to delay the 5G rollout. The planning and design efforts for 5G cellular service started many years ago starting in 2013. The airline industry knew this. My understanding is that the millimeter wave 5G band is well above the frequencies where the airline radar altimeters operate. I also believe that the radar altimeters are a backup capability and are only relied upon when there is a problem with the normal landing system. The airline industry --both the manufacturers and airlines had plenty of time to not only test their devices against mock-ups of mobile phone towers, but apparently did nothing. Now, after the phone carriers invested heavily in buying the bandwidth, and installing hardward all over the country, they are complaining about the risk to flight from the phone towers near airport landing paths. They do not seem to be conducting any tests. In 2019 Korea went active with 5G service and many other countries have also. Did the airlines fly any tests against those systems? I believe this situation is a failure of the airline industry, the mobile phone industry, and the Federal Government -- FCC and FAA. I think if interference is found, it can be mitigated with better RF filters on the mobile phone tower transmitters and the radar altimeter receivers. There are also operational work-arounds, such as reducing the permitted tower antenna patterns around airport landing patterns. Meanwhile, I think the airline industry is just trying to "cover their ass" CYA in case there is some sort of an accident. They were asking for a "short delay" in 5G rollout -- but why a month or so now after not doing anything for 8 years?