I think it's Facebook, nothing to do with you.
I often see people writing they have left Deviantart. Facebook unites so many these days, with people being so busy all the time it's just easier to connect through one place.
I had a long time where I didn't really used Deviatart much, I still don't to be honest. Yours just caught my eye in the Deviations and it had been a while since I saw your work
I don't think it's anything personal, things have dropped for me as well, unless people don't like both you and I's work
It's just that people aren't here the way they used to.