It isn't always a lack of technical fit if someone isn't interested in algorithms and scaling issues. What I am about to say is as a "devil's advocate": I, myself, deeply interested in these issues myself, to the point that I'd never want to work in a company that doesn't deal with these issues.
"Wanting to work on algorithms and scaling issues" is, ceteris parabis, a cultural issue. There's more to building a product than scalability and algorithm design: there's used experience, there's capturing requirements, there's the whole development lifecycle (testing, scoping). It may be true that people who are good at Computer Science may be on average more interested in algorithm design than in (say) requirements gathering or UI design -- but the converse doesn't follow (there are plenty of people who would prefer on the "simpler" issues of software development who are just as competent at algorithms).
"Wanting to work on algorithms and scaling issues" is, ceteris parabis, a cultural issue. There's more to building a product than scalability and algorithm design: there's used experience, there's capturing requirements, there's the whole development lifecycle (testing, scoping). It may be true that people who are good at Computer Science may be on average more interested in algorithm design than in (say) requirements gathering or UI design -- but the converse doesn't follow (there are plenty of people who would prefer on the "simpler" issues of software development who are just as competent at algorithms).