There are already STEEM based forks that works like that - user is given his staking-rewards once per day/week (depending on blockchain) and there is 99.9% spam free space.
The thing is that the same 99.9% of investors do not bother themselves by curating or posting anything. You will have another issue to solve - how to motivate people to do something else other than getting rewards.
Since those blockchains are spam free, the system force users to come and get their rewards daily / weekly or else they disappear.
Now we have illusion that blockchain is valuable because it is alive.
Who gives a f*ck about other forks? Whenever this argument is brought up, people seem to miss the point that there are simply no users on these forks, nor any real innovation or quality apps/frontends.