The sustainable solution is to make people want to power up. Why would they want that?

To get voting rewards and to raise their comment to the top.

This could be done by a curie type org that finds voters to follow, not posters. We have plenty of posters, need more voters. More commenters would be nice too b/c it builds community. Commenters and voters power up and writers take money out and lower the steem price..
Thus far all "marketing" like curie is focused on the writers who take money out to "make a living".

it's no surprise this is causing an accelerating decline in steem price.

Interestingly now that vest are under 90% it makes a lot of sense to power up to curate and comment. Marketing applied now could create a self sustainaing org. People power up, get more voting power and power up more to get more voting power.