Who says this is gonna last long. it might just be a cloud9 or north situation. they play really good and beat the best teams and cloud9 and north won it (Dreamhack Stockholm). it might just be RNG that can win this major, who knows. although i dont think they would last long enough. these teams will be able to study all their strategies. They most likely used their best strategies against Astralis on their best map being mirage. And mirage is statistically the worst map of Astralis. I think Astralis is gonna win it tho. they are gonna be refreshed and gonna win Nuke(of course) and inferno can be really close, but Astralis can win that aswell especially when they are really good on CT side.
sorry that I wrote so much :/
ps. my english isnt that good :D