That would be redundant. On Steemit, everyone's meaningful contribution to the community is recognized for the value it adds ( https://steem.io/SteemWhitePaper.pdf). Each post has USD value that is paid out at the end of the week - 50% to the publisher (e.g., David) and 50% to the curators (e.g., people like ourselves who upvote and contribute in the comment section).

By consistently producing high-quality videos, David engages a community that values "a show that takes the magic and mystery out of cryptocurrency and amateur investing". The values of the community are reinforced through members (aka subscribers) upvoting and commenting, which in turn increases the value of the content, as well as, the size of the rewards pool that gets distributed at the end of the week.

By engaging in high-quality/high-value content, you're effectively participating in an "ether rain" lottery; except on Steemit winning is guaranteed, the jackpot is proportional to your contribution, and you're paid in STEEM.