The reason I mentioned $3-4k being "small" in the post is that this was close to if not at the top of the last bull market, whereas the DHF has spent 350-400k the past few months at the bottom of the market (just as a comparison to the size). Meaning that if we had 10-20x the initial prizes for more contests aimed towards more communities and more consistent ones it could look a lot different, possibly even now with many being gone. Hard to say but personally I think it'd be worth a try at least starting with a similar one.
Dunno about YouTubers, as I said if it's just a one time promo thing I don't think it's going to be that effective as people are just going to see it as a sponsorship/promo or direct ad. I'd rather pay a bit smaller YouTubers to be active here, cross-post and mention hive and what they think about it more often in their videos, maybe even those that create content about something that's somewhat big here, say a photography or gaming community so they can incentivize their viewers to join them and do various activities here.
Well, 3-4k$ can be small or a lot. Even higher budgets have to be very carefully managed otherwise we would risk that people join just for the prizes.
I suggest you to get a look at the Publish0x way of acting in the Contests. Here is one of the last I took part to. Publish0x has these stats https://www.publish0x.com/stats
With 1200$ of budget per contest, there were tens of posts submissions with consequent shares on social profiles.
We can start with the first one about why writers joined the Hive-chain AND why they would suggest people to join it.
To take part into one contest I once submitted also a song, winning the prize for the most original submission that create a huge hilarity.
About Youtubers, I see your point. Having them involved would be the best solution because they can tell the story but showing results and proofs would be the best solution. So I think it can be a matter of involving ONE youtuber that is monetizing his/her channel, telling "hey, do you know that Hive can make you monetize much better and more easily your contents?". He/She starts for some time and once he/she starts publishing results, others will follow because youtubers are growing in number and many of them are starving