That was true when the incentive was for vulnerabilities to be disclosed and fixed for the good of all, but sadly today, vulnerabilities are extremely valuable and so the incentive is for them to be sold to the powerful.
Clickbait and sensationalism is a thing in journalism. It is morally wrong because it spreads disinformation and is harmful to both individuals and democracy, but it is legal and profitable, and we haven't done enough to shun it, so it happens.
Yes it would. Cybercriminals are even more of a threat than spy agencies to most individuals.
[edit: in case it is unclear, I am saying that cybercrime is as strong reason for individuals to use ubiquitous encryption as government snooping not that it is a justification for government snooping]
The responses on this thread seem to prove that Apple knows what it is doing with its security strategy. The fact that people blindly disable protections and end up causing massive malware outbreaks is exactly the reason they are introducing things like Gatekeeper and Rootless. Arguably, this incident is evidence in favor of them locking down Gatekeeper further.
Perhaps because that's more costly? Sometimes the disallowed frequencies exist within a range of allowed frequencies. A hardware limitation would involve filter stages that would add cost.