Investors already make quite a bit, in addition to owning a commodity likely to go up in value quite a bit.
There is a problem with curation however. If more SBD is to be made, it should be for curation. Perhaps SBD generated and given based on voting, vote weight, and distribution? Still rewarding those that have a lot invested in the community, but also the ones that work to find content.
I like the idea, but unless it's specifically a curation reward (like a toggle to receive 50/50 on your curation rewards, instead of 100% SP), I think it would be more difficult to implement. But changing curation rewards from 25% to 50% (as I have seen a few people discuss) and setting it all to 50/50 would be simple modification of proven code sections, which makes for a more elegant solution than my suggestion, but with similar effects.
My suggestion would likely be a modification to the curation reward. Not overly complex, but not overly simple.
50/50 curation rewards would probably be an extremely simple and possible solution. One that I think should actually be done. Not sure it would be enough though.
My idea was based on what everyone always talks about, the distribution of votes. How some people vote for the same people. If you reduce the rewards for people always voting for the same people, and increase them for those with more distributed votes, while keeping it tied to curation, you increase the incentive to go out and find new good content.