Moz is not closing down but this announcement will surely make you sad. As per the tweet
By Moz they said – “We dont have plans to update the survey as we have done in the past”.
thanks for your question! Unfortunately, we do not have plans to update the survey as we've done in the past. ?
— Moz (@Moz) January 8, 2018
Moz has updated their search engine ranking factors study back in August 2015, which was 2 year ago, since then there is no more updates.
The Co-founder of Moz Rand fishkin replied to that tweet in his own way:
Thanks Roger. I might do it solo on my own and publish 🙂
— Rand Fishkin (@randfish) January 8, 2018
Rand is also leaving the moz, as per this source
News source @seoroundtable.