if Ebay wants to keep their customers they should have or add cryptocurrency since many people who are using Ebay have shifted to cryptocurrency.
Ebay has no problem keeping their customers, it's the largest and most popular non Asian auction/marketplace. In fact, they have continued growing despite people's complaints about the platform ifself and PayPal.
Crypto doesn't bring anything related to buyers protection to the table, now let that exactly be why people continue to use PayPal. It's quite easy to charge back and actually win the claims with how biased towards buyers PayPal is.
Ebay doesn't need crypto. Crypto is a pain in the ass to deal with, especially when it comes to all the complaints about failed payments, volatility, and so forth. It's more of a hassle than a benefit to deal with crypto currencies.