I also remember people claiming that Windows Phone 7 will change everything because it was a whole new OS that has nothing to do with Windows Mobile 6.x (ironically, it was later proven to be directly related with only portions rewritten)... aaaaand it failed as it was smite to the ground.

Then Mango (Windows Phone 7.5), as you correctly pointed out, was supposed to be this vast improvement that will finally solidify Windows Phone as a real competitor to Android and Apple. That also failed, as it was stricken down to the ground.

And now the same people are arguing that Windows Phone 8 will completely change the game yet again (how often can you "change the game", before change is actually no longer a change and has lost its meaning?) and, as far as I can tell, it appears to that it too will fail as it gets thrown to the ground.