Musing is a new decentralized platform so they need to grow their user base. To set something like this up is not cheap and doesn't happen overnight.
Profit will take time as they need to get their investment back. Saying that though growth is here and the sky is the limit. Musing make their rewards from the curation on the answers and questions.
If you are upvoted $5 then musing get a percentage of that and I know it varies but would be around 25% of the total vote value. The more that is invested into their SP the bigger the vote value. The more votes they can distribute therefore making more profit.
We are all invested in Steem so the hope is Steem grows in value so the rewards will increase and so will the profit.
Musing.io is first and foremost a decentralized and an immutable community platform. This means that musing profits when the community profits. We need to remember that musing.io is very new and still in the investment stage. This is the time to for them to monitor growth and stick to their business and investment model. Profits will come later.
Although it doesn't mean that musing.io is not profitable. The platform is running successfully and establishing itself is a Dapp to be reckoned with a continually growing user base. The profitability of musing can be divided in two ways.
1. Community growth
Like any new and growing platform musing.io is at a stage where growth is far more important than monetary profit. The growth of user base signifies that the platform would be of importance to the community. Greater is the growth, greater would be the significance of musing.io for this community.
This increased level of utility of musing, both on and off the Steem blockchain ensures that the platform would become self-sustainable and profitable in the coming future.
2. Income/Token profitability
Now we are talking in terms of money or amount of Steem tokens or SBD. This primarily would come through the curation rewards that musing gets through upvoting their users.
Please keep in mind that these rewards are still insignificant to what has already been invested into the platform. At this moment in time, earning profits through curation is probably not even a priority for the musing team. I say this because as an entrepreneur, I understand that this is the time to nourish the platform and not extract value from it.
Note: To gain a better understand about what Musing is trying to accomplish, it would help to take look at their reintroduction post - https://steemit.com/upfundition/@musing/f9rtwn6tj