It's all a question of reference.
If you practice through a bass amp , it becomes your reference for your bass sound, then when plugged DI , you'll think it sounds bad in the PA because you're used to that reference. A PA is a reference too
Then when plugged DI from what? A bass amp modeler?
I would never personally run a bass (or guitar) amp modeler into a bass (or guitar) amp, as I
think that defeats the purpose of a amp modeler. Why would someone practice through a
bass amp then gig through an amp modeler? That wouldn't make much sense to me, if you're
going play live through an amp modeler then IMO you should practice with your amp modeler.
If you're talking about running a DI out from a bass head or combo amp, and using bass cabs
under the bass head or the combos speakers for monitoring on stage, then I totally disagree
with your statements above.
I don't gig out much anymore, but I did for about 20 years just up until recently. I never played
a gig without a bass amp and cabs, running the DI out from my bass head to PA while using
my cabs on stage as my monitor always worked great!
It wasn't like the bass cabs on stage sounded drastically different than the DI out from the same
preamp going to the PA, IME.
Same thing with my little bass amp direct recording rig in the above pics, what I get when recording
to disc through the DI out and monitoring through the bass speakers while tracking is not drastically
different, as a matter of fact it's remarkably similar.
Keep in mind that most bass cabs are full range.

With the 11rack and V-drums, monitoring through my little PA setup while tracking to the computer
sounds damn near identical to what gets recorded.
So my point: If you practice through the flattest reference possible (exit bass amps) , you're subject to get less surprises when plugged DI in a PA.
Keep in mind that people who design PA and tech who install and tune them are aiming at Flattest possible.
Once again IMO and IME, Most PA systems are far from flat, or most reference monitors for that matter.
I've owned 4 different sets of nearfield reference monitors, and no two of them sounded anything alike.
To the OP: I'd say go with the flattest possible , then , there is the question of Power.....
Of course , if you studio speaker are 100watts , you won't hear yourself , that's basic.
I Didn't feel the need specify this , sorry....
It all boils down to what feels, sounds and works right for the individual, there is no right
or wrong way.
It's nice being a musician nowadays with all the different options out there.
I think it would suck bigtime if everyone sounded the same or used the same stuff.
So all of this is just my opinion and examples of the way I'm doing it right now.
