In 2003, Intel was able to reinvent its CPU design center in response to the previous iteration of PC miniaturization (the laptop market was ready to explode, while desktops were slowing down). They did this by running a skunkworks design project in Intel's Israel division (https://en.wikipedia.org/wiki/Pentium_M). After the Israeli engineers were able to show how their design fixed Pentium 4's architectural issues, it became the basis for all successful Intel processors for the next decade.

Intel did great in process technology and the ecosystem around their chips. They were extremely well positioned to grab the smartphone market. Contrary to popular belief, x86 is entirely capable of the TDPs required by mobile phones. The Core m3 has a configurable TDP under 4W while making none of the compromises of Atom. It might have taken another skunkworks project to cut some modules and bring it down to the milliwatt range, but it could have been done. Intel simply allowed itself to be outmaneuvered out of the smartphone market, by complacency and unwillingness to lower the "tax". That worked fine for a decade, but now they're seeing the side effects of the resulting brain drain.