I think what happened is that smart phones took over because people who were not using PCs started using smart phones, and so it seems that phones took over bu

I think what happened is that smart phones took over because people who were not using PCs started using smart phones, and so it seems that phones took over but I think it just tapped into a gigantic market that wasn't really touched by desktop PCs, whose users are mostly professionals, power users, gaming nerds, etc. These groups like the most powerful computing options, and still do but the there are way more non-technical people using a computing device now than before.