This is all on the basis that your pre and sound is entirely based upon exactly what you say, the sound 2 foot from a cab. I certainly don't set up my preamps this way and I'd expect any half learned bassist wouldn't!
It entirely depends on how you wish to adjust your pre for the backline on-stage. Most of my gigs the backline is provided and I don't have a soundcheck long enough to tailor my EQ to get the best out of the cab; I don't need to, as again I am only using it for monitoring purposes. If I heavily shaped the pre to fit the cab, I see where some of you are coming from. Otherwise, I don't whatsoever.