That's pretty difficult to say, even though I think it's true. Why on earth would Liverpool and Spurs be trying to do the same if there wasn't a huge need to do so?
What someone needs to do is substitute the income received since the stadium move, for an estimate of what we would have received from Highbury over the same period.
Then you would see a massive loss given current wages, and player purchases. I.e. We would have had shitter quality players, and be relying even more on Wenger's ability to buy cheap and get results. See Fabregas, Nasri, Adebayor etc....these were the cheapo guys who kept us there....now we're buying Ozils and Sanchez to (try and) compete....we wouldn't be able to do that if we were still at Highbury.
Of course, when the move was conceived as a way of putting us on a par with Utd...it wasn't anticipated that a load of criminals would come in and make it impossible to compete (on a monetary front) under your own steam. Luckily we "almost" can, but for on the pitch inadequacies....which is really why it's time for Wenger to go, as eloquently put by Gary a few posts back.
The MASSIVE difference, is going to be whether a Rogers or a Pochettino(sp) can do the same job Wenger did in keeping us relatively competitive....assuming they have the same financial constraints we did when building our gaff.
But it's different times now. Because those two seem to have backers who will front the money. So maybe they won't have to do it the hard way.