I know IBT is using UE4.. and you make a good point. For every game that we know about, there's likely a couple more that are very early or being kept private until they're further along.
The idea would be to build now for the future. When an SDK is ready it can be shown off and publicized. Once there is awareness within the scene, then it's on the radar of devs, for consideration for various elements of their game when in planning stages. This is building for long term success. Obviously this is not short term gain, this is investment in the long game!
There is at least one whale vote that I can think of that could get behind this.