From a marketing standpoint it seems dumb to bring attention to the fact that your game has been in Early Access for two years.
Right or wrong to a lot of people that isn't going to be seen as some great milestone or achievement - it is going to be seen as a failure that only serves to upset some of the customers.
I predict they, for the most part, let that date go by without any kind of major celebration or mention of it. The only way I see them using that date is if they have a release date to announce.
