One rule of thumb I've seen writers on Anandtech express several times is that any given microarchitecture can cover at most about one order of magnitude for power consumption. This leads to laptop/desktop-oriented microarchitectures that can scale at most from about 13W to 130W by tweaking clock speeds and voltage. More recently, the high end has dropped down to at most about 95W for non-server chips, but it still means you have to go back to the drawing board before you have a CPU that can work in tablets and smaller devices.

So far, Intel has shown that they aren't very good at simultaneously developing two parallel product lines of CPUs. Their tick/tock strategy of alternating process shrinks and microarchitecture updates has been working great for years, but Atom has clearly been neglected. Prior to that, they had the P4 NetBurst architecture and the P6-based Pentium Ms on the market at the same time, but NetBurst hit a wall and the company lost a lot of ground to the Athlon 64 before they could come up with a high-performance successor to the Pentium M.