http://mamedev.emulab.it/haze/2011/05/12/political-roadblocks/

The first two paragraphs, for your reading pleasure...

Mame 0.142u3 made big strides towards the MAME/MESS codebase merge, however,
unsurprisingly the move has since hit political roadblocks, and the majority of
the work I put into doing this for the release has once again been reverted.

It’s a shame that in this day and age there are people involved in the teams
who have no interest in progress, no interest in advancing the project, but
just want to block changes and prevent progress being made entirely for
political reasons, and personal grudges.