Comparing Eth with BNB is like comparing apple with oranges. Eth is completely decentralised crypto that is maintained by its community of developers, while BNB is centralised coin whose blockchain is controlled by Binance. Seeing the rise of crypto many centralized coins were launched like EOS, XRP etc. But they are against the ideology of crypto. I am not surprised whether binance has 82% or 50% of BNB, since they control the blockchain they can manipulate token distribution according to there desires.
Reading this I thought you talk about BTC and ETH 
ETH isn't fully decentralized either. In the past several decisions were made by a small minority of developers that just pushed their "vision" or rolled-back mistakes.
Centralized to some degree isn't necessarily bad though. Of course, with Binance as a centralized exchange it is no surprise that BNB is fully under control of Binance.