If you are making an argument for something and people aren't convinced, who's issue is that? The tech community wants the general population to be against installing backdoors. If people aren't convinced or don't care, we can take a couple of stances:
1) well, people just are too dumb / don't care enough / stubborn, we've done all we can and it is what it is
2) the message isn't getting through, let's try something different
We have been trying different things since at least the 1980s and the Clipper chip debacle.
At _some_ point, this quits being a failure of the tech community. _Some_ people simply are not teachable, because they refuse to listen. No "something different" is going to convince someone of something they don't want to believe.
P.S. You didn't say "issue" before, you said "failure." That it's an issue is indisputable. Assigning blame seems counter-productive at best.
1) well, people just are too dumb / don't care enough / stubborn, we've done all we can and it is what it is
2) the message isn't getting through, let's try something different