When I was trying to fly out of Vietnam pre-covid lockdown craziness, I was able to find several airlines that had a section of the plane for your dog where provided it was small enough (I think it was under 7kg) they would sit with you in a couple of rows that were reserved for people traveling like this. There was a surcharge but I was flying from Vietnam to USA and it was only going to be like $100 extra.

Although I rarely encounter it, I agree that people who are skirting the system to get their dogs on the flight for free should be stopped from doing so and also agree that if you are so nervous about flying that you can't possibly do it without your fur pal with you then you are a danger to the flight and need to find another method. There are exceptions of course like ex soldiers with PTSD, but they would likely receive a professional service dog, not just some rescue that they designated as their service animal.

Who knows why it ever got allowed in the first place but I believe it was a silly idea and it was always going to get stopped anyway.