Why is swig 3.0+ not just "swig"?

I didn't see any related questions; apologies if I missed an answer to this.

SWIG 3.0 has some significant fixes, some of which are related to Python 3, and I think it is very strange that simply installing and running 'swig' gives SWIG 2.0.12 even on Ubuntu 15.04.

As I understand it, SWIG 3 is not like Python 3; it's simply the next version of SWIG and there are no deliberate backward compatibility breaks. Many Makefiles and configure scripts only look for "swig", and I do not think these should need to be adjusted to use the current version of SWIG (3.0.5).

I propose that the "swig3.0" package provide the "swig" executable, and that the plain "swig" package depend on the "swig3.0" package instead of "swig2.0".