Opera Mini was big, depending on where you were. If that brand recognition isn't why it's installed it's definitely part of why it stays. So the story starts earlier than described.
I don't think it's uncommon, the rule is more that you can't rely it not being hacked (with sufficient time, skills, etc.) than vice versa.
Whether or not it is depends on how much effort the world is willing to put into it.
There's plenty of software/devices that have never been hacked, but the ones that really test the rule to me are those where the effort to secure them is closely matched with the opposite, iOS, Denuvo, games consoles etc.
FWIW this attack is more commonly being attributed to Israel, partly because it endangers the deal (sanction relief for enrichment limits/inspections) the US is trying to reestablish.
This forum used to be pretty interesting back when the mobile OS market was more diverse https://www.nairaland.com/phones