Hyper Bazooka - Weapon of Yesteryear?

[False Prophet]

One could say that the humble bazooka is the first weapon ever intended for a MS to use - a machine that can dance around CIWS and missiles while downing spacecrafts like flies. It's simple, cost-effective, versatile, and packs a punch. So how did it almost go extinct by the end of the first century of U.C era? It was then either missiles, grenades, or Sturm Faust. And by 0110s, Beam Bazooka replaced as the go-to when a Gundam (F90/F91) need heavy firepower.

Oh, but there is one thing I must point out: the real-world Bazooka has no magazine. And the length of the shell is half as long as the launcher tube. We can conclude that the Hyper Bazooka works more closely to a 120/125mm smoothbore cannon used by tank rather than a recoiless rifle, which relies on both kinetic energy and explosive to inflict damage.

Any answer?

[HalfDemonInuyasha]

I can only guess because small missiles, grenade launchers, and sturm fausts are even cheaper, lighter, more versatile, and can be mounted on the mobile suit('s shield) itself rather than having to be a separate, large hand-carried weapon, thus allowing the mobile suit to still carry a beam rifle, beam machine gun, or something while still having that similar heavier firepower with those missiles/grenades/sturm fausts.

[Massignifico]

Beam Rifles are just as good at blowing up ships while having more ammo (at the point where in Zeta era even mass produced ms can replenish their e-cap in combat) and if rifle not enough there are bigger variants. In the end after OYW the only ms which use bazookas are Rick Dias and some Gundams most likely because it's trademark that Dom derivatives use bazookas as main weapon (Dreissen didn't for a long time but joined the club in Unicorn) and protagonist Gundams as backup weapon. The only other example I remember is Sinanju which used it against General Revil battleship to counter anti beam smoke.

[Gelgoog Jager]

Focusing on mass production units, during the Gryps Conflict the main units used by each faction relied mainly on beam rifles, with a few exceptions actually using explosive weapons:

AMX-007: 1xBazooka
MSA-099: 1x Clay Bazooka
RMS-117: 1x 2-tube shield missile launcher
RMS-106: Optional 2x 3-tube waist missile launcher

During the 1st Neo Zeon, we saw a drastic increase in the number of units equipped with secondary missile launchers:

AMX-006: 2x 14-tube binder missile launcher, 2x 4-tube binder missile launcher
AMX-008: 2x 9-tube binder missile launcher
AMX-011: 2x 8-tube backpack missile launcher, 3x grenade stored in shield rack
AMX-014: 2x 12-tube backpack missile launcher, 2x anti-ship backpack missile launcher, 2x torso grenade launcher
AMX-101: 2x 2-tube torso missile launcher
AMX-102: too many to individually list, but they total 44 missiles from fixed missile launchers plus another 22 missiles from optional equipment, for a grand total of 66 missiles.
AMX-107: 2x 4-tube forearm grenade launchers (2 rounds per tube), 6x missile mounted on wings hard points*
AMX-109: 8-tube torso missile (subroc?) launcher
MS-14J: 1x 8-tube backpack missile launcher, 2x forearm grenade launcher

*in the 7th UC OVA, we are shown that Bawoos can actually carry far more missiles on hard points across their bodies.

As for 0093 and further, I want to point out that besides sturm fausts, another piece of equipment that helped overcome the need for rocket launchers is the grenade launcher attachment found on many weapons such as machine guns, beam rifles and even shields, including OYW OVAs such as 0080 (MMP-80 and RGM-79's bullpup gun), 0083 (MMP-78). I bring this up since the Geara Doga is a very important example of finding alternatives to bazookas, namely through the used of fixed grenade launchers (shield), sturm fausts and another grenade launcher on its main weapon, totaling 9 explosive weapons. More importantly, it's shown in the UC OVAs that both older and newer Neo Zeon MS can borrow the aforementioned equipment to further rack up their explosives count, such as in the case of the Zssa and Geara Zulu. We also see some GM IIIs borrowing the shield with 2x 2-tube missile launchers of the Jegan.

In short, the 2nd Neo Zeon War has:

-AMS-119: 1x grenade launcher attached to beam machine gun, 4x grenade launchers mounted on shield and 4x sturm fausts.
-RGM-89: 2x 2-tube shield missile launcher, 1x 3-slot grenade rack

I won't cover the 3rd Neo Zeon War since most units end up borrowing older pieces of equipment and in many cases MPed units use unique weapon loadouts (and I don't want to have to describe load outs such as what the Geara Zulus from the 5th OVA used from inside the Garencieres).

Finally, I recommend that you check the Geara Zulu's unique-looking sturm faust and the MS-06A (from MSV-R)'s early Zaku bazooka (also included in the HGUC kit of the MS-05B). The former actually looks more like a 1-shot bazooka rather than a sturm faust and given that it looks more complex than the disposable stick left from other sturm faults, I'm willing to consider that perhaps its meant to be reused unlike its predecessors. The early Zaku bazooka (the one with the long grip on top of the tube) is depicted as the type that needs to be manually reloaded after each shot, and for which the MS-06A (and most likely the MS-05B as well) carries a small "bazooka bullet rack" (as per the MSV-R manga) on its skirt with 3 bazooka rounds.

[BrentD15]

Don't forget the Sinanju and Unicorn Gundam using bazookas.

[Gelgoog Jager]

I actually forgot another relevant case: the Jegan's bazooka. Although it seems it wasn't used during CCA, the original version of the Stark Jegan was depicted with it and by U.C. 0097 it would appear most Jegan variants are seen using it.

As BrentD15 points out, by U.C. 0096 the Sleeves have a new bazooka which is used at least by the Sinanju and the Dreissen, while the Unicorn Gundam gets another one.

On the other hand, I also recalled another interesting weapon: the 200mm Lange Bruno Gun. Though not a bazooka, this unique weapon (a sort of anti-ship rifle), it also fits the idea of a MS ballistic main weapon after the OYW. AoZ Reboot has at least one AMX-101S which was modified from its original configuration into heavy weapons type using the same backpack by U.C. 0091.

As a side note, with a Geara Doga around also by U.C. 0091 according to Missing Link, I think we have more grounds to think that the design was already around at least since early U.C. 0089, before the end of the First Neo Zeon War, which would explain why both remnants groups (Char's and those on Mars) have access to the design.