Good variety of posts on this subject. In an ideal world where all houses are on reasonably level ground with good access and no restrictions on water usage and there was a high volume of high end work, it might be best to have a truckmount, if you could not only afford to buy one, but continually generate the volume necessary to sustain the overhead.
We do not, however live in an ideal world and only 20% of operators will work in the higher priced end because that is how it is.
It doesn't exclude operators who opt for portables , rotaries, encap's, from being high earners, far from it, in fact, many will run much more profitable businesses, so, whichever set up you go for, it depends on YOU, rather than the tools you use.
Big isn't always better, ability and application will always deliver over flash and brash.