When it was 75/25 rewards the whales continually lost their % stake in the platform as they upvoted others(because 75% of the upvote went to who they upvoted and they got 25% back). With 50/50 rewards the whales can keep their % power as long as they continue to upvote anyone.

Scenario, a whale with 1million HP

Under 75/25 - posts little himself, upvotes tons of people. Weekly basis of the whale giving out lets say it is 1,500 USD worth of Hive to who he upvotes and 500 back to himself.

Under 50/50 - same scenario as above, upvotes tons of people. Weekly basis of the whale giving out 1,000 USD worth of hive to who he upvotes and 1,000 back to himself.

hey hey, ho ho, 50/50 has got to go!