"The point is, great leaps forward donít come from tweaking primitive existing technologies, it comes from replacing them with totally revolutionary concepts."
If that's the case, there has never been a great leap forward yet, as pretty much everything developed to date has been the result of a long series of incremental discoveries and improvements over decades or centuries.
Radio wasn't a sudden discovery, for example, it evolved step by step from England's William Gilbert's initial investigations of magnets and their properties, published in 1600 in Latin (the universal language of the day) as "De magnete, magneticisique corporibus" (or "On the magnet"). Among other things, he determined that the smell of garlic does not affect the operation of the compass. Hans Christian Oersted of Denmark discovered that compasses act strangely near electric currents, and Joseph Henry of the U.S was able to make a practical electromagnet from that information. Gugliani Marconi of Italy figured out how to transmit signals using an oscillating magnetic field's effect on iron filings, and later induction in wires, and Scottish/Canadian/American Alexander Graham Bell discovered how to modulate voice into electricity.
Granted, Gilbert had no idea any of this would come from his observations of lode stones, but none of it would have been possible without a seemingly unrelated phenominon known and studied 400 years ago.
Often "inventions" seem to come out of nowhere simply because nobody is aware of or pays attention to them until they become refined enough for new uses. Plasma TV technology has been around since the early 1970s, in large computer displays (orange or green usually) where CRTs couldn't be made large enough or with adequate resolution. IBM had a huge plasma terminal in 1983 - that technology was spun off and eventually ended up added to Panasonic, making the TVs popular today. Plasma displays were also used in fighter planes.
It was gradual refinement that led to giant full colour televisions that people can actually afford these days, but only people actually working on them noticed it.
LCD displays you probably have noticed - from the watches that projected hard to see grey shadows of numbers that went blank when it was too cold, to the high performance displays competing with plasmas today. Plasma display development essentially was parallel to that, but not in wristwatches and calculators so you wouldn't have noticed it, making it seem like a sudden invention.
What makes things seem like sudden breakthroughs is when a technology used for one thing becomes refined enough to replace another technology, or find an application it wasn't suited for before - it changes from hidden to prominent. Eventually solid state lasers are cheap enough to put in a photocopier, and you suddenly have an affordable laser printer - but expensive laser printers were around before that.
So, after all this, I guess my point is that looking for great leaps forward from technologies that don't exist just doesn't work, because all technology, whether it exists now or not, takes a long time and a lot of work to improve, refine, and make into something usable. The "great leaps" are just illusions.