I remember reading a post where someone talked to customer service and asked that question and the rep stated that they are selling more now then they were when it came out 2017- 20 18. Of course this is third or fourth had info so who knows? But it would kind of make sense. I have notices a lot of early thread comments in late 2017 and 2018 a lot of people were really bashing the Equinox saying it could not possibly be as good as their current model of detector. Funny, I remember a lot of the users names of those early Equinox bashers and look at their profiles and see they own a 600 or 800.
Part of the problem especially with the 800 was that people (like me) would buy one and not really know how to set it up. And more often than not my either copied settings or what I thought were good settings were not for the sites I was hunting. I was essentially using a badly tuned 800 through ignorance and thus was not having very much success with the 800 comparted to my trusty AT Pro.
Some people advised you should just noise cancel, ground balance and pick one of the standard modes. Back then, I thought that is for total beginners and I had been detecting for many, many years. Wrong!!!! The 800 is a very fine detector in the standard modes. It takes a while to learn to master the 800 for some (like me). Wasted 3 months or more trying to tweak advanced settings and really screwing things up.
So yes, I can see now it still selling well as people report their successes on the various metal detecting forums and on their youtube metal detecting videos.