STEEM provides value for Steemit by creating a tangible product to reward for participation. Steemit's value to STEEM, thus far has fostered interests and grown the market capitalization. When the paydays start dwindling, interest is apt to ween as well. There is a finite number of people that will be interested in being involved with crypto in any way, STEEM included.
They're watching all this and may or may not invest when the time is right. The good news is, you do have a growing member base that has made a lot of money here. Let's hope they come back in after they've cashed out. There's one sure way to ensure future growth...re-investment.