While you have certainly made huge and impressive improvements, I still don't think I could call that "solved". I think any latency is still going to put people off when it comes to writing on this vs. paper.
our goal for solving it was to get it down to where it wasn't a detriment for the writing and sketching experience. one of the first things we did was gather data and read what research there was on what kind of latency was noticeable and lead to writing feeling "wrong".
so we solved our goal, but it's always possible to get better.
So obviously without actually trying one myself I can't say that you are incorrect, but certainly the demo video you provided still has a feeling of wrongness. Its like with animation, we're still stuck in the uncanny valley but you are definitely climbing out of it.
this is one of the reasons we need to get this in the hands of some kind of ambassadors that can test for themselves and give us some validation. imho the video doesn't do it much justice.