I've got no argument whatsoever with the "the cabinet is part of my instrument sound" position, since most bass cabs are far from flat and uncoloured, and people pick one with a sound they like and adjust the bass/amp/effect/cab setup to sound best to them standing next to it.
Just don't then assume that putting a mic in front of it -- carefully placed or not -- means it will sound like that out front.
It can do given all sorts of provisos (good soundman, enough setup time, good mic on isolating mount, good placement with multiple drivers, good stage, low bleed/cancellation with FOH), but any of these not being the case means it very often doesn't.
If you can get as good a sound to your ears on-stage using whatever electronic gizmos are needed to do this (amp simulator -- or amp! -- cabinet simulator, distortion...), DI and and a flat monitor, the odds are *much* higher that it will sound close to your "perfect sound" out front.
Even if you think this setup doesn't sound as good to you on stage as a good old-fashioned Ampeg (or whatever) cabinet and mic (choose your favourite), a simulator+DI solution can still sound better (i.e. closer to what you really want it to sound like) out front.
Not always, but very often -- just look at what's needed to get FOH sound the same as your ideal on-stage sound with a cab + mic, and work out the odds.
Or feel free to take the view that it's your job as a musician to just get the sound you want on stage and it's the soundman's problem to replicate this out front, and his fault if it doesn't work very well. Then when the audience complains (or you listen to a recording) you can blame him, so you'll be happy even if nobody else is...
I prefer an option that maximises the chance of *everyone* being happy, regardless of which end of the jack lead I'm standing at