Why have bayonets gotten shorter?

I think this article from the "Load Out Room" was mostly click bait but I bit anyway.  This part of the article (before the vid that actually explains why) got me a bit jaded though...

As late as 1900 the bayonet was thought to be fully one-half of the infantryman’s tactical armament. But of course, that was mistaken: the bolt-action, magazine rifle,  the Maxim machine gun, and the barbed-wire entanglement, were soon to demonstrate that cold steel and élan were no match for 20th-Century defensive arms in prepared positions. This was clear in the siege of Port Arthur in the Russo-Japanese war, although some particularly blockheaded European officers couldn’t learn from foreign experience, and would have to have their own, to the detriment of a generation.

But the bayonet wasn’t obsolete, because of, as we’ve said, what the bayonet is. And what it is, is a psychological weapon. The Argentine draftees around Port Stanley in 1982 faced the horrors of modern war with fatalism, if not exactly equanimity. But two things put them to flight, or surrender: thoughts of Gurkha’s kukris, and thoughts of cold steel bayonets. Likewise, that 2004 British unit in Iraq did not so much increase their combat power when they fixed bayonets, as they increased their psychological dominance of the battlefield. The psychological effect of the bayonet is two-sided: it strikes fear into the enemy at point end, and stirs confidence in the soldier behind the bayonet. Such de minimis subtleties are the foundation stones of many a victory.

Story here. 

I'm gonna nitpick a bit.

They start off by saying that the bayonet has been supplanted in its role because of modern weaponry and defenses but go on to say that as a psychological weapon its still has a role to play.

Does it?

Against trained opponents?

Against opponents with automatic rifles?  Grenade launchers?  RPGs?

I'm just not sold that it was thoughts of Gurkha's swinging their fighting knives (machetes) that made the Argentinians quit.  Not sure that the Brit unit won decisively because they fixed bayonets.

Bayonet charges means an assault thru a fire swept landscape before you can close with the enemy.  If its house to house then that means maneuvering a longer weapon in a confined space.

Perhaps its time to drop the term bayonet and calls these weapons what they've actually become....attachable fighting knives.