There are heaps of people that RP in private and I can visually see the numbers of public and private posts, so the activity is there.

What you may find that even though a lot of people are home in isolation and quarantine, they are still living busy lives and aren't exactly in a holiday mode. People aren't going to the movies, aren't going to holiday destinations, and even in some places aren't leaving their home except for groceries. That all hinders creativity greatly as you are physically limited in activities and have to stay within your home.

There have been studies and checks done to show that people have generally become more laxed and lazy while at home during this period, and people have been sleeping more often as there's no reason to rush to get to a workplace by 9. There's home schooling aspects too which reduces free time as well. Those who are still working, me being one of them, are dealing with so much workload that it is physically exhausting. 
Everyone flipped their lives and still dunno where they stand. 

So I don't think the site is kinda dead, I just think that people have been distracted with other events in the world and it's taken a toll mentally and creatively. We're not in a bubble immune from the world and if people are struggling to work out what to cook for dinner for the 10th night in a row as no take aways are open, they're gonna struggle to RP.