The article misses the point a bit. There are 3D maps of the world, or rather, you can make your own on a weekend. Topographic data is out there for most things, the problem is just it's very inconsistent and of course, resolution. And I guess for the whole world you do need a decent computer.
To prove my point, here is some art I made [1] from open data (I think NASA) with Blender and QGIS, meaning free software stack on very much a normal computer. My model was the state Schleswig Holstein, a german county, but as said, you can find data for pretty much everything. The resolution is not astonishing, but enough to spot Germany's only high sea island, the "Wattenmeer" where tide causes some spots to lie below water level on average, the mouth of the Elbe and more cool stuff when you know where to look.
My point isn't to downplay the effort of EarthDEM, I just want to make more people aware of what is already very much out there :)