It also helps that Archie’s way more level-headed than Maxie, despite his plans being slightly stupider. He realizes his plan’s a bad idea 30 seconds after it starts raining, whereas Maxie throws a fit when Groudon cheeses it, blames you of all people, tries to rob the Space Center and blow up Mt. Chimney out of sheer spite and/or desperation, and only begins to question himself in any way after you and Steven have wiped the floor with him yet again. Then, when he confronts Archie once Kyogre’s woken up, he blames Archie for everything, even though Maxie did pretty much all of the stupid/dangerous/stupidly dangerous/dangerously stupid shit in the game.
In Sapphire, after you stop Kyogre, Archie sounds so damn dejected and pathetic when you speak to him again. By contrast, in Emerald, he actually seems pretty relieved and takes the foiling of his plans very well. I guess having a certain someone by his side makes all the difference in the world...