Listing on top-level exchanges costs huge fabulous money ... most projects don't have that much money. And many experts agree that listing on the top exchanges for millions of dollars does not justify itself from an economic point of view.
A fact. And if you add to this that exchanges have a habit of doing delisting of coins, then the question arises why exchanges take such a huge amount of money. What's the point of spending fabulous sums on this?
Not all exchanges take big sums of money to list tokens, there are some that check tokens and its team because they cares about their clients