Being listed on a exchange as an coin isn't all about the money. Exchanges also look at the reputation of the project. Because if they don't and the coin turns out to be a scam then that exchange that listed it will face the consequence. So if you look at Binance the coins there is quality. Because you need money and trust to get listed.
that's true but that needs a lot of qualifications especially from the product must be audited but the agreement between the exchange and dev will also discuss how much fees that must be paid by the team as a part of requirements.