The thing with Maradona for me is that although he was on a completely different planet in quality terms in his era (with Cristiano Ronaldo maturing to fulfill his vast potential at more or less the same time, there hasn't been such a gulf between Messi and the best of the rest), at both club an international level where he found success, his teammates were obviously way beneath him technically but far more on his wavelength in other important physical and (most importantly) mental aspects of the game.
Those Argentina sides in particular were not a bunch of highly-talented constant national team letdowns like they have been in Messi's time - they had no Di Maria, Higuain, Aguero type flatterers. Ruggeri, Valdano, Goycochea were Maradona's strongest World Cup compadres, and not a one of them were shrinking violets; they brought it when it mattered. As much as it is utterly beyond question that Diego's astonishing gifts pulled them to heights they had no right to reach, it can also kinda help the cause to have a very solid-if-unremarkable team of reliable battlers propping up a bona fide genius or two, as opposed to a collection of flashy mercurial superstars who cannot be depended upon when crunchtime comes, which is how Messi's Argentina can be pretty fairly characterised. He has often been the one who looked most likely to haul them across the line, the producer of those standout moments when all around him have appeared lost, although obviously not in any way that could feasibly be compared to Maradona in '86. Maybe if his national team possessed less technical quality but more mental strength and physical resolve, it would've given him a firmer foundation from which to take the bull by its horns in those big tournaments? It's hard to say, but there are always factors at play other than Messi simply underperforming on his own.
Outside of those international competitions, he delivers in the biggest games, under the most intense crunch-moment circumstances, so regardless of whether he's in his comfort zone system-wise and around familiar settled Barca colleagues of many seasons (indeed, since he was a kid), it's not like he flatters to deceive. Who's to say the greatest international players were not in their own comfort zones in those national team setups where they made their biggest impacts? International squads for the big boys these days are far more widely dispersed than they used to be (not England though, obviously... heh); in the past, they were often dominated by just a few clubs in their domestic league, who would encounter each other far more regularly and get used to one another much quicker. It's difficult to pin down the exact reasons why individual footballers flourish in certain big tournaments and not others, and if your not-so-familiar teammates are pretty shit at pretty important stuff like making the right decisions when trying to set you up, protecting and making space for you, and putting away chances you lay on a plate for them, then good luck with that, whoever you are.
