To truly be satisfying, bass must be visceral, not just aural.
The first time you experience a superior sound reinforcement system with extended bass response, the sympathetic vibrations in your torso will take you by surprise. Perhaps they will be accompanied by a chill running up and down your spine. This is the sought after response, for both you and the audience.
This
cannot occur with
just IEMs, or floor wedges.
Transferring the primary duties to FOH, subs, or sidefills is not "obsoleting" the bass amp, those items have now
become the bass amp. You may personally travel lighter by only bringing a pre amp/Di, in rack or pedal form, but
someone has to bring the "racks and stacks" to push
dat bass onstage and FOH.
We used to say "The bass ain't snappin' til your pant leg's flappin'", and used SVT's and Acoustic 370's to prove it. Thankfully reason has prevailed, and the trend now is to keep stage volume under control, but the thrill of experiencing "live" music is the physical reaction to gut shaking, spine tingling
BASS.
This has an intoxicating effect on audience members of both sexes, perhaps affecting females more pronouncedly . It spurs them to dance, folds them into the music, "primes the pump" (if you will), and will never occur if the audience is just wearing earbuds.
No way.
Solid, deep, resonant, extended bass, and a shot of kick drum punch are what unceasingly drag them to the dance floor.
So, until we can remotely tap into the central nervous system, there will always be a need for an electro-acoustic transducer, and associated power supply, of sufficient effectiveness to reach that CNS through vibratory excitation.
And that, my friends, is the definition of a bass amp!