But they are factory ready for shooting video. Just not with a 180-degree shutter. Cell phones, action cameras, dashcams etc all lack NDs, do they not shoot video? Ugly video is still video.
I'm not sure we'll ever see hybrid cameras come with built-in NDs outside of a few models that are very video-biased, in the vein of an S1H, GH6, etc. It just adds too much bulk to keep the traditional photo-camera form-factor.
You have to have room for an assembly a bit wider and taller than the sensor to completely slide/rotate/flip out of the way. Ideally you'd have a clear replacement to keep the backfocus to the sensor consistent. And this is competing for space with IBIS and mechanical shutter mechanisms.
If global shutters ever happen without DR or sensitivity compromises, that would clear up some room I guess.
You could use a fixed E-ND that doesn't need to move, but then you're always losing whatever its minimum setting is... a stop, two stops? Low-light sensor performance hasn't improved enough lately to absorb that difference and stay competitive.
IBIS is too valuable to photographers (and many videographers including myself) to trade it for ND. Adding an ND to my lens or lens adapter is massively easier than adding and using a gimbal.
