Yup. The reader asked for a sub-plot involving their companies, something that you wouldn’t really put in a Super Friends comic.

This gets back to what I discussed a few pages back. Maybe Batman does draw the editorial ire of Jameson, but we don't see that. We never see all the pages of the Daily Bugle in a Spidey comic. How do we know there isn't a Gotham City correspondent on page 9 or 10?

It's a fair question you've asked, but I am very much of the view that we are not privy to every aspect of characters' lives. We don't see everything. That can include the mundane (we've never seen Spidey take a bath, although spiders are notorious for getting stuck in baths). We see Jameson's vendetta against Spidey. We see front pages of his paper, most of them dismissing Spidey. But perhaps throughout the pages, there's a Metropolis correspondent, Gotham City correspondent, etc. Same with a government liaison. Maybe the JLA have one and we just don't see him or her. Maybe they just don't have one.

On a forum years ago, I remember someone saying something along the lines of, 'It made no sense for Spidey and the Transformers to be on the same Earth, why hasn't anyone mentioned giant robots before?' Again, we see what we see. "Off-camera", perhaps Cap and others have had regular meetings where they keep the Autobots on their radar. But in their monthly books, we don't see it.

It's a leap I am willing to take.

Thank you, although it's the great responses from everyone that has made this topic work!

It's important to state that whenever I post a topic (on any subject), it isn't necessarily absolute. There can be nuance and there is exceptions to the rule. Same with life. One could debate, say, whether the space program is worth the money or not. Whatever side you fall on, you can possibly think of exceptions to the rule. A person who is pro-space program can probably think of instances where it isn't value for money; a person who is anti-space program can probably think of the benefits of space exploration.

So while I robustly stick with the shared Earth preference, I realise there are exceptions. I mean, there really would have been no good reason to have Star Trek be routinely bumping into the Spectre or Darkseid back when DC had the licence. So sometimes being in a separate universe, or completely divorced from the mainstream books (as DC's Trek was), can make sense.

Can Aquaman and Namor even co-exist on a shared Earth? I'm not intimately familiar with either character, but aren't they both the King of Atlantis? And don't their respective versions of Atlantis differ considerably, with mutually exclusive histories?

That is a good point. Of course, even within the Marvel Universe, there are conflicting versions (hasn't there been more than one incarnation of Dracula?). And a Hercules very different from the one we know appeared in an early Avengers tale (the one where they fought Immortus). But, still, good point.

DC’s got it too. The Atlantises of every comic series were different, and they all had mermaids there! The Supers had Lori Lemaris and Jerro the Mer-Boy, Wonder Woman/Wonder Girl had Manno/Ronno (also the Mer-Man/Mer-Boy) and we don’t talk about Aquaman and his Atlantis where he was made King because he was the best choice (plus Mera from another dimension).
And also Mars. And Jupiter. And stuff. Wonder Woman literally had a characterisation of Jupiter in an issue and a different one literally less than a year after. And she also had villains from Mars. The Duke of Deception and the actual Mars were from there. Which gets in conflict with J’onn’s backstory unless you remember Mars is totally big enough for it.