>What makes them dead? It's still the only consistently supported thing I encounter online.
online is dead too, no app uses paypal, and plenty of online merchants take credit cards more than paypal; they even offer their own credit cards.
paypal hasn't innovated at all in over a decade, and people are scared of the way it will hang on to your money with little recourse.
PayPal is, unfortunately, not dead. It's used by RMV in Germany for a start - only way to pay for a bus ticket in the app/website. No credit or debit card, straight up PayPal account.
"No app uses PayPal"
You have already lost your plot with that claim. Just because you don't use it doesn't mean it is not widespread.