If we see it from the current marketcap and the ecosystem, BNB have a room to be king of altcoin. The total volume of transaction on BSC is not lie, the chart showing that increasing rapidly. One of the reason is because many user crypto looking for low cost of transaction fee.
It's true we can see for ourselves that until now more and more people are using Binance Smart Chain,
indeed it can not be separated from the low transaction costs,
and when it comes to transaction fees, it seems that ethereum is going down too
BSC has gained a lot of popularity recently specially with it just being supported by the available ethereum keys and addresses, the switch was easier for both developers and users. But the most important thing boosting the change was the price and speed of the BSC network. Ethereum too has improved a lot by this time and as they continue to improve, I believe developers and users would feel much easier to use Ethereum again when the fees and transaction speed are similar.