Really? Every sound engineer knows exactly how to make every bass player sound good? And it's always the same solution, without any need to listen to what the bass player says or sounds like?
Sorry, but that's just as laughable as saying that every bass player has a great sound and impeccable technique.
Indeed it is. The truth of the matter is that like so many things in life; a DI is used instead of a mic is because it's
easier. When it was first introduced, bass rigs (such as they were) were often laughably inadequate and the DI box solved a lot of problems and didn't have any phasing or bleed issues that came along with it. At the time, it made a lot of sense. It became the norm.
Rick Turner once observed how passive mixing of pickups (even with most active systems) is an inferior way to mix them but it's been around so long it's become accepted as standard and it sounds
normal to most people. Just because it's the norm doesn't mean it's the best way to go...
This is why we have the classic scenario (if I had a dollar for every time I've gone through this...) where a soundman preemptively assumes a DI for the bass without having
any knowledge of what the band is going for, then treats it more-or-less like a binary system. Plug in, play a few notes...OK, we're done...it's on, level is fine. Tone? Whatever...it's just bass....if it's boomy I'll roll off some lows and if it's muddy I'll crank some highs....jeez.
As many have pointed out, it is indeed much trickier to correctly choose and place a mic and make that work. A guitarist will often refuse to go without his amp sound. A lot of keyboardists too; especially if it's organ with a Leslie....after all,
it's part of the sound isn't it?
With bass you've got the inertia of an accepted practice working against you (hey we've been doing it that way forever) plus the fact that for many people....hey it's only
bass fer chrissake. What are you getting worked up so much for?
Indeed, that mindset would suggest that bass heads and cabs that color the tone in
any way at all should be avoided because that not what anyone besides you is gonna hear so why delude yourself in the first place?
I'm sure folks will disagree and that's fine but of the literally thousands of gigs I've played and/or seen I have
never (unless he is the bandleader/guy writing the check) seen the bassist get anywhere close to as much time and attention from a soundman, live or in the studio as a guitarist will typically get. And if they do ask for more attention they're usually being "difficult".