|Style over substance|
The elusive Philosopher's stone is believed to be the object of medieval alchemists' quest for the transmutation of base metals such as lead into gold. We now have the science and even the technology to achieve this sort of thing, though it costs rather more to build and operate than the difference in price between lead and gold.
The phrase "Philosopher's stone" may also be used to refer to any general goal that is currently unreached but if achieved, would allow for major breakthroughs in science/energy-production/wealth-accumulation/etc. It can also be a metaphor for enlightenment and reaching the pinnacle of human abilities.