I don't think this is a problem specific to musing platform, its more about the entire crypt space. Given that the market is down for long time and the value of steem has reduced , the reward is not significant for blogs / posts / answers. So that takes many users away because when they see there is not much they gain, they don't feel to spend time here.
Hopefully things are going to be good once the market recovers. Steem especially is doing good compared to other crypt, it has increased after the recent update on Hivemind.
And coming to the platform I think, the team behind the musing platform is already working towards spreading this more, so that we get users from all segments onboard here. Once the price corrects, things will be smooth for them as well.