I can't shake the feeling that you're objectifying something that is fraught with subjective factors. You can't talk about articulation (or indeed muddiness, coming out in the mix, etc) without talking about the bass's role in the context of the other instruments in the mix. I feel that by bass gets better articulation for how I play my bass with the people I play with. So automatically I think that your arguments are not as comprehensive as you would lead us to believe.
Have you thought about the idea that maybe your lack of success with Alembics may have to do with your preference with how the bass, and just as importantly the other instruments, are brought into the mix? I'm not saying that you're not open to different mixing but you may be a victim of your own preferences in some systematic way which you may not be aware of. You may have a quanitifiable set of expectations, which inherently involve a complex relationship between all the instruments, such that Alembics don't fit so well. In this sense, you, as a musical experimenter, are effecting the results of the experiment.
The only reason I say this is I've heard tons of recordings and live stuff where the Alembic came out awesome (off the top of my mind Disco Volante and California from Mr Bungle come to mind). I've had a lot of success playing with others Alembics achieving a sound that we all love. And if it still sounds weak to you, maybe that's just your preference. Maybe you like to hear the bass and the other instruments do other things than I do.
I think the argument that if Alembics were so great, then everyone would be playing them assumes that people play instruments for purely musical reasons. You must admit you know that isn't true. My experience is that most people, whether they know jack about basses or not think Fender is the shit. And I always point them to Sadowsky (also available in passive, ash, etc), which to my ear is just as good at achieving the Fender sound, and you wont have to worry about that neck buckle at the 18th fret in 5 years due to 40 year old construction techniques (if I believe what my guitar tech tells me).
As far as Fenders, you can't just ignore the cultural factors that have led the Fender sound, and indeed the Fender style of playing to be widely accepted. I'm not sure this remotely implies an inherent goodness of Fenders in a mix of any particular type of music, unless you include economic and cultural factors that might increase success (such as playing a certain way with a guitar play who's used to a certain type of bass playing. That might, however, affect people's understanding of what instruments *should* do in relationship to each other.
And once again, I've heard some great jazz bass. But if I was in that person's position I would approach the music in a different way, just based on what I like to hear.
