Speaking very broadly, I'd say "less" is not "more" if having (or doing) less means a person is deliberately limiting him- or her-self in some way. A really crude example would be the person who goes from happily dabbling in a dozen different crafts to grimly concentrating on knitting, not out of lack of interest in the other things but because s/he feels it is somehow better to do just one thing.
Generally speaking, I think the smaller the physical/mental/emotional box we put ourselves in, the less interesting we become, the fewer friends we have (because we don't give ourselves room or resources to cultivate new relationships), the less inviting our space is (e.g. the millionaire who lives in a hovel and never has company and never improves his/her environment), and the less we contribute to the world.
It is one of those "balance" questions. One can live in a small, minimalist home and still embrace a variety of activities and interests; or one can live in that small, minimalist home and have such a small appetite for life, or such a narrow mind, that nothing sticks.
I guess what I'm getting at is that LESS, in our physical environment particularly, can indeed be LESS if we fall into the not-uncommon trap of "well, all I have is this little empty box, so all I can do (or be) is Little Empty Box Person."
LESS - in the physical environment - can be MORE if we use physical space and emptiness to invite creativity and adventure into our mental/emotional lives.
