If supporting steem means feeling compelled to hold onto an asset that's lost 90% of its value, then it's doomed to fail. Steem should succeed regardless of the actions of individuals and what they decide to do with the rewards they earn. Again - I feel the same with Bitcoin and Ethereum and their miners too - nobody should ever feel guilty for selling. They're providing liquidity for those who want to buy.
If a currency is only there to be sold, then said currency is most likely not going to be very successful.
I don't think anybody would expect of you to keep 100% of all rewards that you're earning (due to taxes & co.), but seeing your constant power-downs, it does give the impression as if this is simply a way for you to gain more satoshis. #freeMoney
Now, I get your points about being in an alt-coin bearmarket, selling for BTC, etc, but comparing Bitcoin miners to your activity as a content creator, is not really accurate.
Miners have costs that are 100% produced for the single purpose of mining Bitcoin. They're not mining ETH with those machines as well. At least not at the same time. So if they want to continue to mine, they need to sell or have other means of income generation if they want to bet on a bull-market.
As a content creator, you're recording your own videos, which are then published primarily on youtube and then either linked inside a Steem post or re-uploaded on 3speak/dtube. Now, if you were only uploading them on Steem interfaces (3speak, dtube) and were attracting viewers to them exclusively, then I would agree with your point about your costs needing coverage. But since most people are probably watching them on youtube, those costs are not exactly the responsibility of the Steem reward-pool.
A way to solve this dilemma would be to create Steem exclusive content; either whole videos or longer videos, where the last 20% of the video is only going to be released on 3speak, etc. Longer videos could be advertised at the start of the videos, similar how Logan Paul's podcast "impaulsive" is 10 or 20 more minutes longer (roughly) on Spotifiy & other podcast providers, in comparison to youtube.
That way, your actions would be in line with your intentions of helping the Steem ecosystem by bringing your own viewers to our wonderful platform.
And don't get me wrong: I appreciate your videos and they bring valuable insights.
The irony is, if you check out this guy's social blade, he makes far more posting his videos on STEEM then he makes on YouTube, yet he frequently comments and engages there.
https://socialblade.com/youtube/channel/UCpceefaJ9vs4RYUTsO9Y3FA