Another thing to consider is not just final beam specifications at full power, which are a little better for SM, particularly at higher power levels, long distance projections outdoors, large events where the beam has a long path etc, but the matter of the constitution of beam profile and colour mixing as a result. Most projectors don't just use 100% modulation at all times, especially for those fades + blends, this is where SM pays for itself in professional use, MM is not bad but side by side you can definitely see a difference in most applications.
A good SM build will deliver breathtaking mixes, with an extremely sharp red, to the point I was amazed it was so bright compared to green, on multiple balanced set ups, across the power spectrum.
There is a reason the top manufacturers go to the hassle of building SM reds. And the really good ones, if treated with respect, will stay perfectly aligned for an extremely long time.