I'll admit readily that this is a reaction to the lasgun appreciation thread. No negative animus against that, and the lasgun is certainly appreciated, but even that thread is afflicted by a view that I find incomprehensible.

I really have to ask. Why are people looking at the Guard and looking at lasguns only?

Because that has never been the case in lore or tabletop. Look at Gaunt's Ghosts and tell me how often the flame-troops and support gunners get screentime. Let alone Larkin and his long-las, for blight's sake. Look at Ciaphas Cain; aside from small-scale intrusion missions, do we ever see them far from their Chimeras? Every time we see Guard in action, they either have special weapons right there in the squad, or they're mechanised and thus the Chimera carries the heavy weapons, or they're moving with tank support. The closest we can come are the conscripted dock gangs in Helsreach, and that's a special case, because A) they're not Guard, that's a contingency effort, and B) it only half counts because each dock gang has a Steel Legion storm trooper with it anyway.

There has never been a usage case of Guard engaging the enemy with lasguns only.

The only case where this is even remotely true is in art, and even then they have vehicles.

Why is it that people never seem to open the armoury?

Because the Guard have one, people. Ten lasguns can't beat a Space Marine, but they don't need to, because your squad has a plasma gun. Ten lasguns will take a while to stop a Rhino, but they don't need to, because coming up from the left is a Sentinel squadron with a lascannon. Ten lasguns won't do a thing to a Chaos Land Raider, but they don't need to do anything to it beyond shatter vision blocks and muck up external armament, because the Leman Russ exists.

Flamers, sniper rifles, grenade launchers, plasma guns, meltaguns. Mortars, heavy bolters, autocannon, missile launchers, lascannon. Not yet counting Chimeras and Sentinels, which just increase the options available. No Guardsman ever engages the enemy with lasguns only.

Not yet going into the Guard's other claim to fame, its vehicle park.

No analysis of the Guard is ever complete, or close to accurate, without taking into account the Guard armoury. Even the case of a line infantry regiment with absolutely nothing else in support, that regiment will have its weapon teams, whether they're separated off into their own squads or part of the line squads themselves.

The lasgun is the building block, the base of fire, a weapon that is good enough to have some performance on the battlefield. Against human-equivalent targets, it'll do nicely. But it is not the only piece. Any threat you care to name can be adequately met by a weapon from the Guard armory that isn't a lasgun.

The Imperial Guard have an armoury. The Guard are more than just lasguns.