Actually the ratio is:

75% (50% Steem/50% Steem Power). The steem power is a long term investment (2 years) which includes interest on your Steem Power. Steem power is useful for many reasons, which includes influence for your own posts (if upvoted), and for you to influence earnings on other peoples posts/comments. It "shares the wealth" if you engage with your community. You still have your steem, but there is no guarantee if your earnings will be the same (given market fluctuations).

25% Curators: those who used their steem power status to influence your earnings.

Quite simply if you earn 4$ at final point you can trust you officially earned 1.5$ worth of Steem (give or take) right then and there. Steem power helps the system flow so that users do not abuse upvotes.