I used to do phone security for a living. I've seen a handful of cases in person. The bigger issue is that most of the time you don't know it was the phone that caused your problems. One day your bank is drained and you don't know why.

There have been several zero days that gave anyone that wanted to the ability to own your phone with a text that you never even saw because the phone doesn't show you command texts.

https://www.bleepingcomputer.com/news/security/apple-zero-click-imessage-exploit-used-to-infect-iphones-with-spyware/

Unlike the good ol' malwares that let you know that you're infected by deleting your files or messing up your system, modern malware authors are profit-oriented and will do everything they can to make you unaware that your devices are infected. Then they'll exfiltrate your data and sell them on various underground marketplace such as this one.