Late to see this. But the answer to your question is because even though they are superficially accomplishing the same end result, they are not nearly doing th

Late to see this. But the answer to your question is because even though they are superficially accomplishing the same end result, they are not nearly doing the same thing. Your smartphone is running a full blown modern operating system, with all the processors and memory and store requirements. The pager is likely running a very lean embedded processor and doesn't have nearly the same energy requirements.