Earlier quoted context omitted.
This is true - and WebOS was legitimately innovative here. At the time neither iOS nor Android could run more than one app at the same time. This was both an architectural matter and a UX matter. On iOS and Android at the time, all apps were full-screen. When you switched to another app, the previous app suspended execution entirely. The OS would keep the memory footprint of the app warm in RAM if possible, but back…
The Nokia N900, running Maemo, also supported multitasking in 2011. It was just toppled by a similarly dedicated team of executive fuckups.
That's why those OS were mostly used by geeks and power users, and "regular" users were using feature phones that "just work".
One of the strength of iOS and Android were to create a completely different userspace that what we had in desktop OS, more adapted to mobile. They combined the "just works" aspect of feature phones with the power of smartphones.