Logic circuit designs in industry
It is a mistake to focus only on gate count or transistor count to select the "best" implementation of a function. Modern synthesis tools are much more sophisticated.

We usually have timing constraints on a design, so the synthesizer may choose an implementation that requires more transistors and/or more silicon area just to make the circuit run fast enough.

Also, the intermediate results of some complex function might be useful. Suppose we needed to have \$\overline{AB}\$ as well as the exclusive OR. The third (pink?) implementation provides that for free, the others do not.

Circuits that are not fully restoring (i.e. pass signals through transmission gates) are usually not used as standard cells in digital design because it is so difficult to characterize their timing parameters as a function of output loading. Such circuits might be used inside custom macro cells, or in full-custom design at the transistor level.