That makes me wonder if the problem is lack of attention to detail as opposed to the connector itself? I have about 10 of them with full exposure to rain and snow, and no use of dialectric grease to boot, with no moisture related failures. My first rule is to make sure they hang vertically with the fully sealed camera end on top, so there's little or no risk of water getting through the gasket/seal on the other end. Another detail is to make sure that the square-cross section seal between the connector halves isn't curled. The connector half with the removable seal has to be tightened after the connector halves are mated. And finally, that the seal is there at all. I have a few times swapped cameras where the seal stayed with the old camera pigtail, and I stupidly didn't notice that there was no seal on the new camera pigtail.
Of course not every camera that is not installed with dielectric grease will fail, just like a camera can fail if dielectric grease was used. It's a percentage game and some luck involved as well. There are many cameras in operation that didn't properly waterproof and have ran for years.
Heck before I knew any better I buried an analog camera connection with no waterproofing at all and it ran for 8 years before I upgraded the system and got rid of the camera and system. By all intents that thing should have died years prior. It was all rusted and crap but kept going.
But yea, there are steps one can make that will determine whether a connection will be problematic or not.