It is rather hard for startups to collect money. And if they colleted enough money they must change where to spend money - on the development or on listing on big exchange.
If I were the owner of a startup, I would prefer to invest in development and promotion. Perhaps the trade will be organized on one of the decentralized exchanges. If the project becomes successful, then the centralized exchanges will offer listing on their own initiative.
It is unreasonable to spend funds on listing without creating demand.