There clearly hasn't been any major deployment of this - especially at the scale of Blaster or Conficker.
It's "trivial" perhaps for a single device but every device is different and it'd require its own exploit code, exploit mitigation features cause it to be difficult to actually exploit too - making it quite problematic to deploy in practice.
It's not trivial - there's a lot of devices and exploiting mitigation techniques to deal with, there's not even a reliable PoC that works on real-world devices with ASLR enabled.
These exploit mitigation techniques and differences in builds have basically saved it from becoming the disaster it sounds like at first glance.
I guess to answer your question, yes, yes we are that moronic. Not many people will care unless it's proven rapidly and readily exploitable.
It's been about 2 years since Stagefright was disclosed. Are we still waiting for it to explode? And if so, can you give a timeline for when this explosion will occur?
No it's not. Where are all of the Stagefright exploits? This was supposed to be Android's security armageddon according to the scaremongering bloggers. And yet nothing happened. According to Google's telemetry of over 1.4 billion phones there has not been 1 case of a Stagefright exploit in the wild. So your assumption that Stagefright is "trivially weaponizable" is inconsistent with your knowledge of Android security and mitigations.
The only texts I ever recieve nowadays are automated (2FA etc...). Even though unlimited texts come with every SIM.
SMS has remained the great constant throughout all these games. Turns out people don't get in touch if you don't use WhatsApp but shows how much they care eh!
The triggering factor for this was the worms though. No such similar thing exists in the Android space.