The fact that it's difficult to reverse-engineer Google's technology is an accident of the kind of products it makes: web services. You can access the product while the "secret sauce" remains safely tucked away in a data center.
At the opposite end of the spectrum think of a company like Intel investing into WiMAX. Developing that standard was not cheap, but almost by definition it was something that required disclosure of the end result. Intel can try to recoup the initial investment by selling chips implementing the standard, but competitors can always undercut them on price because they didn't have to spend any money coming up with the initial design.
There is a lot of technology that's much easier to reverse engineer than it is to develop. Especially with software, where it's often very easy to dig out a copy of the firmware from a competing product and decompile it.
You might think this kind of stuff doesn't actually happen, but in the 1990's American companies hated working with the Chinese precisely for this reason. They'd take an American product and copy it right down to the silk screening on the PCB's, and sell the result for cut-rate prices.
