Signal could easily start offering named, verified accounts as a paid service for say, businesses, to have secure texting to their customers. Heck, named personal accounts for this would be ideal to. This is a service which has direct value to me (I already pay for an email domain for the same sorts of reasons).
Signal's product is the sort of offering which ticks so many security textboxes that it would be a no brainer, and getting even 1 big enterprise pushing it out to their customers would guarantee adoption.