Legacy apps
Windows tablets have been around for years, and always had the ability to run legacy x86 apps... They never sold well, because those legacy apps were designed for use with a keyboard and mouse and are generally difficult if not completely unusable on a tablet based interface.
Apple succeeded because they made a tablet which ran apps specifically designed for use with touchscreen input. And they were also very smart to differentiate ipad from their keyboard/mouse targeted systems.
Microsoft want to tie the whole thing together, so they are trying to sell tablets by associating them to a product that while well known, carries a lot of negative baggage.
People expect a product marketed as being windows, to:
run legacy apps (windows rt does not, and such apps run poorly on x86 tablets)
crash
be malware prone
Or to put it another way, there is no reason why any android device couldn't run traditional unix applications, as the vast majority can be easily recompiled to run on an ARM cpu. Indeed most already have been, and there are a number of ARM based devices which do use traditional input peripherals and which do run traditional applications.
So despite how easy it is, there is virtually no interest in running traditional apps on touchscreen devices, and far more interest in creating new touch friendly interfaces for such programs.