I have not heard any news that there are 30 round magazines for a 9 mm, only 15-17. Wow.
30 rounders have been around for a long, long, long time. They’re commonly available but not commonly purchased. Most of them are *much* longer than the gun they go in, so they’re not very popular. Generally speaking, they are not considered practical for carry usage, so they are limited to range use and, in the case of the police and foreign countries, use in fully-automatic machine pistol variants that are carried openly anyway.