the ROI for a successful author can be much higher than for the old-skool services, so that will (theoretically) attract more top-tier contributors.

For this to happen, my assumption is that somebody else’s rewards would need to be much lower - initiating their migration to other services.

I don’t know what kind of margin these voting services work with but the only way to avoid the “robbing Peter to pay Paul” analogy would be if they were willing to reduce their margins. Or maintain a higher voting capability themselves. i.e. the delegated amount will earn a consistent x% vote per STEEM delegated and the top authors are competing over the services own y STEEM vote value.

That could work.