I for one thinks it is this way - you don't expect him who brings more value to the table, to get the same accolades with the person who brings lesser value to the same table. What I mean in essence is this; a number of musing users just write a line of answer and believe they should get an $10 upvote because they are answering questions on musing.
But what's the difference between your one line of answer and my own 3 to four paragraphs, five or four lines each of answers? Let me tell you. A layman will get more value in the longer and more explained answer I gave than he will get from that one line of answer you gave.
My answer will enable him to understand perfectly well the question he is asking and take action according to the answers almost immediately. I believe these are the things the moderators or curators at musing look at when curating answers.
First of all, the length of the answer you have given. Secondly, if your answers are well written and not plagiarized and thirdly, the kind of value your answer provides for the user and the rest of the community. I think this is how the moderators judge answers before curating them.
Sometimes musing.io will upvote. Then there might be promotion bots that can be used to upvote if the "post to blog" option is selected. There is also the posibility that someone asking or answering has a large amount of steem power or several accounts each with a moderate amount of steem power.
There are a few reasons that I've gathered from checking out musing (1) when you answer a question there are people behind the scenes working from musing that will manually curate your answers if they like what you have wrote or feel that your comment adds value or provides a strong answer to the question. It can all depend on if your comment is seen, the timing of who is online and reviewing answers and whether or not they liked your response. On the flip side, musing gives you the ability to post your comments or answers directly to your steemit blog as well. It's here that you can earn upvotes from your followers or bid bots or anything else people use to promote their posts to gain upvotes. If you're getting steemit related upvotes, the total of the upvotes you have received overall will show on musing as well as your total overall earnings. It doesn't necessarily strictly represent upvotes that you received just from musing. Hope this helps.
$3+ is likely to be people using bid-bots to promote their answers. You can check this by looking at the list of user names in the upvotes (on a site like busy you can see the amounts upvoted and you can cross-reference to steembottracker).
Musing maximum upvote seems to be 25% of their power which is currently close to $0.90 - $1.00. So this is what you would expect from a really good answer, plus a few smaller upvotes from other Musing users.
Those are most likely people using bots. Musing from my expierence very rarely gives out huge upvotes. At this time it looks like most people get a 1-3% vote which is going to be about $,25-$.76 at this time. If the price of steem goes up so will the upvote amount.