There is a speculation which i very much agree with saying that Chelsea only bought strong, expensive and luxurios materials yet the establishment itself is another matter.
Nobody who has money as much as the Russian does can not do the same thing if they want to, since it's purely about money, not about achievement: an enormous consumption that doesn't automatically result reasonable production.
Team establishment is a different dimension with team purchase. Establishment needs process: just can't be reached overnight.
You see the evidence in their last result against southampton. They won, but is it because of the expensive buyings? not at all, one own goal and one penalty.
On paper, Chelsea must have won with more than 2 aggregates against team like, no disrespect, southhamton whose total buying is far lesser than one of Chelsea's cheapest buying.