Why does a flush beat a straight in holdem?

[GrunchCan]

Two players are dealt drawing hands in HE. One is dealt suited cards. The other is dealt connecting cards of different suits that don't match the opponent's suit.

The flop comes and hits both opponents - both have thier best draw. There are 9 cards that will improve the flush draw, but only 8 at most that will improve the straight draw. Very often, only 6 will improve the straight.

It seems to me that it is much easier to make a flush than a straight. Is my suspicion correct?