I think that they were really never made for long periods of wear and tear. They were a temporary ruse that would have reconciled the unknowing citizens of Earth into not panicking and boarding the Axiom and other ships. The only reason WALL-E has survived is because he has a massive pool of replaceable parts to take from.
Facinating perspective! And it’s true, we see it a few times in the movie. With all the other WALL-Es breaking, there is ample supply for new parts.
But then we get back to the question on how did Wall-E devise this wise idea to survive amongst his fellow companions…
Luck, I think, started it off. He may have also been more individual thinking than the others, overriding his programming to simply continue working, and used the old parts of his companions. From there, while he could repair himself if he broke a part or two, his companions shut down in droves, and built up his pool of replaceable parts.
there could be other Wall-e’s around the earth.
That’s a possibility! But the tag line of thee movie is ‘The last robot on Earth’.
The last living robot?
True, but wasen’t that the same for I Am Legend? Instead of robot it was man.
Well, technically in I am legend, the last man wasn’t really the last. There were other, infected humans around. Maybe someone should do a fanfic about the other wall-e’s that might be alive across the world?
Can a robot truely live?
Maybe the other Wall-E’s don’t live as humanely as our Wall-E does. And maybe they’ve survived through a possibly more sustainable part of the landscape, that BnL had strongly influenced their company in the United States (since the Axiom lands there).
Well their where multiple ships, perhaps Axiom was programmed to land where WALL-E ‘lives’, and the other cruise liners were due to land in other sections of the world.
Yeah, that could be true. the ‘Jewel’ of the BnL fleet…
Although the ads were programmed around that world, maybe the other continents have their own Axiom that they appropriately name for something else.
No one questions that Stanton originally came up with the idea about “the last robot on earth that someone forgot to turn off” or something like that. But as I’ve said before, that was in 1994 and the movie evolved, including dumping the idea of the gels in the last two acts during pre-production in 2006. While searching for something else, I came across a post dated in late 2007 in the "Wall-E Plot thread, now in the Archive forum. It was a plot synopsis released by Disney at that time. This is going way back to like 9 months before our movie was released!!
to realize that WALL•E has inadvertently stumbled upon the key to the planet’s future, and races back to space to report her findings to the humans (who have been eagerly awaiting word that it is safe to return home).
Now what’s wrong there? I didn’t show the whole press release, but you should be able to glean the error from this short quote. The error is the humans have certainly NOT been eagerly awaiting anything. They don’t even know what Earth is. They only know they have overstayed the length of their 5-year cruise by about 700 years.
So it just goes to show that key errors can be made. Whether this one was accidental or purposefully misleading we just don’t know. Remember the Captain yelling “Get that Robot!” in the previews? Never happened. The story was developed in a state of flux and nothing was set in stone.
But we are still left with the question.
The other Wall-E units were not alive and Wall-e realy needed those spare parts.
A shotgun might have been involved
Maybe they ran out of battery our something.
I think they may have been turned off.
But whenever I watched the movie, I always wondered how he is the only one still going. 
Did it ever confrom every one was turned of but that Wall-e?