(Edit: Beaten to the punch, but only just) Firstly, I'd like to nip the misuse of 'quantum leap' in the bud there. As a fanciful TV show title which potentially created tiny changes in other people's lives at the right place to change things for the better, it was an apt title, but in general, people misuse that term so badly.
'Quantum' comes from the Latin word 'quantus', meaning 'how much', and was coined to represent a single unit of quantization of things in physics (an alternate was already in use- the Greek word 'atomos', meaning literally 'uncuttable', used by physicists to refer to atoms which they believed, at the time, to be the indivisible units of matter). This means a 'quantum leap' is the smallest change possible (although the idea that it has a potentially a huge effect wouldn't be going too wrong either). I haven't seen the phrase used in the mainstream media for quite some time as I'd like to hope and believe they've all been educated otherwise. 'Revolution' is certainly a far better term.
By all means, educate your friend and feel smarter in the process. I'll resist kicking other Escapist members in the shins until they become a repeat offender despite having been educated otherwise.
Now I'm off my little soap-box... Minecraft! I'm with the others here in saying that I don't think Minecraft is a revolution. The idea just isn't that original (being original is hard these days, but not impossible), drawing from Infiniminer and, either transitively or directly, from Dwarf Fortress. Everything in Minecraft is a spin on something done before, and as I was trying to list as many as possible, I found the amount of games that contain such elements exhaustively long.
Minecraft isn't about originality. It's success stems from a few other things- the style of the game has a certain charm. It's been well promoted and marketed through non-standard channel. It also is fairly solid in execution. Given how many mainstream games are bug-ridden nightmares on release (and some remain so, to this day) making a solid, relatively glitch free and pleasant experience definitely has its value. It's almost another niche in the market- the well-made game.