It's true. Even though Binance bought CMC it doesn't mean that it isn't fair that Binance is top 1. Even if they didn't bought CMC binance will still take the seat. Like you said, Binance has a great reputation overall. And one of the golden coins. So there's no doubt that binance will dominate the chart.
I don't think Binance needs to buy CMC to get first place there, because indeed they have become the trust of the Traders at this time. What the Binance Team needs to do is they have to stay like this, maintain their good reputation forever so I'm sure their Exchange will remain No. 1 in Crypto world.
Now this is real test for them as they can keep maintain their good reputation and trust because we have history of big falls so if they able to keep this all then surely this could be very good and positive impact of crypto on world and they will understand this all is safe and good investment for long term with security.