not to defend Shiftypig's POV, but we should point out that another marvel of engineering- the Erie Canal, was proposed 24 years before it was finally completed. It took 15 years to build and was obsolete in as many years, replaced by the steam engine, which could also deliver goods in the winter (as it's operating system didn't freeze...)
If the Apple tablet isn't released for 39 more years, I will be forced to see your point...