More honestly it is "Technical people can make great startup founders, but first filter on if they can recruit one other person to work with them." In any team of two, most of the time there was one person that had the idea and drive and asked the other to join them. A technical person with this type of skill, that is willing to spit the ownership of a company with someone else, is much more likely to have the skills and talents to run a high growth startup than someone who has not recruited their first person to join them.
I would imagine that when interviewing a pair of founders, whether consciously or not, people place one of them into the CEO role and the other into the CTO role. Don't most startup teams split up work like this pretty quickly?