>>How would a phone or tablet do that app?
In 2011 it wouldn't- that would be ludicrous for the anecdote you present. There will be plenty of similar examples, just as there are plenty of examples of people here still using VFP profitably for the foreseeable future. That doesn't mean that VFP is the best choice for everybody or that desktop always is the best choice.
Even in the niche you describe I'd be watching mobile closely: by 2013 some device manufacturers say they'll be able to cast a private interactive virtual 3D screen up to 100" across, providing far greater design benefits than a 20" fixed screen. At which point tabs and other traditional GUI concepts will be a PITA and customer device choices may cost you a fortune if you're locked into a minority platform.
"... They ne'er cared for us
yet: suffer us to famish, and their store-houses
crammed with grain; make edicts for usury, to
support usurers; repeal daily any wholesome act
established against the rich, and provide more
piercing statutes daily, to chain up and restrain
the poor. If the wars eat us not up, they will; and
there's all the love they bear us."
-- Shakespeare: Coriolanus, Act 1, scene 1
