I wasn't around for the previous 50/50 but my understanding is it was changed arbitrarily

Back in Steem's infancy, we had

1. 100% hyperinflation - total currency supply effectively increasing a million fold after 30 years
2. n^2 curve - someone with 1000 times your stake gets a vote 1,000,000 times your weight

It would have had severe problems but it was unlikely due to the 50/50. As you can see, the rest of the package is entirely different from those extreme measures.