While I agree with your premise, I don't think it has bearing on this discussion. Whereas unwanted calls, texts, etc are a pervasive problem across all telephony and particularly cellular devices--one that the FTC has taken lead on dealing with, they do not particularly affect and are not preventable by any hardware manufacturer.
Can you use an Android phone without a Google Voice number? If not then this also exists on iPhones, through the Google Voice app, just possibly tighter integration. Google Voice != iPhone; Google Voice ~= ATT
Different carriers have different support for Google Voice. Sprint has native Google Voice integration where your GV number is your carrier number.
On other carriers the integration isn't as tight, but the experience is still superior to the iPhone Google Voice experience in that Google Voice on Android integrates with the standard phone dialer so you just make outgoing calls like you normally would using the standard dialer (or any other app which invokes the standard dialer) and they go through Google Voice.
I'd agree that the hardware manufacturers aren't necessarily to blame, someone should be championing a real spam roundup API that lets you easily click a button when you get a text or phone call and report the sender as spam to the FTC. The FTC is the logical place to start that, but I don't see why Apple or Verizon or anyone couldn't get the ball rolling.
