Most of those "dead" apps were not under active development and had no income flow. Making a "trivial" change to an inactive project means rebuilding software which you have shelved for some time.
If you are actively developing software, adding Intel support to a build is pretty much just clicking the option to build a Universal binary. Adding a flag to an existing build a lot easier than dusting off an old app and making a bunch of tweaks and a new build with near zero chance of return on that time invested.
