Why compare Tendulkar with Bradman? Even Sobers does not match up to Bradman. If we look at cricket historically, people who stand out would be WG, Spofforth, Hobbs, Bradman, Sobers among other players till the late 60s. From the 70s on, there have been far more players in vivid memory because of the video and the memory being more fresh. There were a host of great fast bowlers in the 70s and 80s. However, now we look at Lillee and Marshall from subsequent decades more. They have stood the test of a few decades, so to say. In that parlance, there have been a host of players from the 90s and 2000s and it is difficult to say who would stand the test of time. Warne, Lara and Tendulkar seem like the 3 players most likely but you never know. Every subsequent year, I find Gilchrist more of an anomaly, as there just doesn't come a player like him.
I guess when we look at these greats, the fact that no one came like them played a large part in them standing the test of time. There was no one like WG, there was no one like Bradman. Wilfred Rhodes was a legendary figure but he was forgotten a fair deal as Sobers came along. Jonty Rhodes was some one who we all thought was a freak. People think of him as just another great fielder after fielding standards improved (though I still regard Jonty very highly, even by modern standards, but that's besides the point).
There are the numbers of Tendulkar - the ODI and Test runs. The ODI runs will never be eclipsed and I can't see any one going a lot ahead in terms of test runs, even if some one does manage to cross it. There are the 100 international hundreds. Tendulkar will be more of a WG Grace like figure I think, in 70 years time. People will be split as far as his greatness in the very elite pantheon of greats like a Bradman and a Marshall, just like they are about WG in ways. A lot of numbers can have that jarring effect.