Don't the fibres break down when you chew fruit?
Anyway, surely lots of smoothie and a tiny bit of veg is better than tiny bit of smoothie and tiny bit of veg? Smoothie must still have all the vitamins, anti-oxidants etc.
In any case, for most people, aren't smoothies too expensive to buy and too fiddly to make as an ongoing several-times-a-day contribution to a staple diet?
To my mind this is one of the finer points of helathy eating to wory about once you are already living the near perfect concern-free life