So Tennis Warehouse takes a hypothetical situation (read matchup) and gives their biased opinion on it and then quickly gets into a fight over a hypothetical situation. Are people becoming dumber by the minute? Or do they have too much time in hand and they have no clue as to what to do with that? Why not do something creative instead and watch something that inspires you to do something about the world? Can you imagine Steve Jobs arguing all day over a hypothetical situation on a message forum? If the Universe was so predictable then trust me, you'd all stay at home and do nothing, but it's not.
Take that Agassi vs Murray matchup for example. On what ground do you even make a hypothetical matchup? For all I know, Murray is only half way through his career and we have no idea, no clue as to how his career is going to end up in the end. Even a hypothetical matchup/situation needs balance in order for you to compare and deduct results. And then there are so many other things that you need to take into account.
I am not even going to touch the Sampras vs Djokovic one.