But you're only relying on anecdotal evidence with respect to Trumper or Bradman's prowess while dealing with spin, aren't you? Nobody ever saw them tackle a spinner who could have the ball on the proverbial yoyo and make it talk in tongues day in and day out like Murali or Warne did, so what makes you so certain they would've fared any better? I understand it's fascinating to compare eras and hypothesize over what may have happened, but it doesn't make it more fact.
There have been many spinners with wonderful control of flight, length and spin. Laker, Lock and Tayfield are names that spring to mind when it comes to my example of Harvey. Verity dismissed Bradman the most amount of times, if I remember correctly. Valentine and Ramadhin are two other excellent spinners that often go unmentioned. I think that anecdotal evidence is incredibly valuable as it is essentially the charm of the game and adds insight into what actually happened.
For example, Sehwag made 67 runs (that's off the top of my head, don't hold me to it) on Boxing Day last year. From the statistics, it will go down as a fine performance from Sehwag. If you had actually been there, which I was, you would have noted that he looked highly uncomfortable against anything short pitched, scored approximately 50% of his runs through edges that ran down to the third man boundary and had relatively simple chances dropped on 11 and 58 (once again, from memory), both off the bowling of Pattinson.
You can ignore the anecdotal evidence but it's what gives life to the history of the game, and I have no doubts in my mind that when Bradman described O'Reilly as the "best bowler" he ever saw, he wasn't just saying it.
On Harvey and Bradman, Ashley Mallett said this: "[to them] smart footwork helped eliminate the real danger here and that was being anchored to the crease while a clever spinner could weave his spell."