As Moxie Marlinspike once said, the fine line between facism and social democracy is choice. In order to exist in certain social groups, you have to expand your scope of choice to be able participate in society. In my experience using TextSecure/Signal for a decade and having convinced all of my friends/immediate family/significant others to use it, the majority of new people that I have encountered even with Signal installed on their phones, do not use it. It’s unfortunate, but most people only care about privacy to a certain degree, if at all. What I usually do is bite the bullet with SMS for a bit. If things are going somewhere, I eventually convince them onto Signal. If things don’t pan out, then not too much damage done.