Smartcards aren't dead, they are all around us in sim cards and credit cards.

> They died when everybody ditched Java applets for web.

How's that relevant? Are you saying no one uses Java anymore?

Well, Java for frontend / client side not anymore, since Java applets are insecure and can be exploited easily.

Java applets for browsers and Javacards have nothing in common except the name and the language.

Many smart cards use an extremely minimal version of java, so I imagine that java applets were able to interact with them more easily.

I'm not saying that writing for Javacards is easy, but that's not the problem here. There is plenty of software written already

https://github.com/EnigmaBridge/javacard-curated-list

It's just didn't catch on, there's no thriving community around it. You have the software, you have the hardware (search for JCOP21 or JCOP3 on Aliexpress), but no users.