I’m familiar with your thoughts on how the games try and paint Mew as the ancestor of Pokemon and how backwards their logic is claiming it’s due to Mew having the DNA of all Pokemon. That, as you’ve pointed out multiple times, is not how ancestry works.
I wanted to share with you an idea I’ve had about how I’d handle the Mew situation and what your thoughts about it are. For me, since Mew is the only Pokemon barring Ditto that can learn transform, I really like the idea that Mew could be the ancestor of all Pokemon, or at least the Mew species. In how I’d handle it, Mew would be #1 in the Pokedex and would be the original Pokemon that could change shape at will. As the curious creatures as they are, mews explored endlessly, tackling any environmental challenges by changing shape into the various Pokemon species we’re familiar with to suit that environment. Over time, those mew who grew older and decide to settle in their areas in whatever shape they were in, over thousands of years, lost the ability to transform and remained in that shape as whatever new species they were. Because so few environments are comfortable for Mew’s natural form, and/or so few mew continued to travel endlessly, modern day mews are fairly rare, hence their legendary status. This would really help explain a lot of artificial Pokemon since the mew that originally became that species took on an artificial form for one reason or another somewhere down the line, rather than Pokemon like Klinklang, Electrode, and Klefki existing and being able to breed in some degree for no particular reason.
Some days I really hate Mew.
Okay, so. This interpretation. I think my initial, instinctive reaction is that it’s… too tidy. Too neat. Deep down, I want the Pokémon world to be governed by processes that are as unpredictable and complicated and messy as real evolution, and being able to just say “everything was really Mew all along” seems… too easy? It does make breeding and egg groups easy to understand, I’ll give you that, because this way most or all Pokémon species are a roughly uniform number of generations from the common ancestor, and all based on a common genetic template, so the only thing left to govern reproductive compatibility is exactly what kind of changes were made to the basic Mew form – hence, egg groups.
There must be quite a few Mew still around, though, because some of the “artificial” Pokémon are only known from recent times – Voltorb imitate mass-produced Pokéballs of the type that were supposedly invented only during Drayden’s lifetime (not clear exactly how old he is, but certainly we’re talking some point in the 20th century), and Professor Juniper’s research points to the sudden appearance of Klink around 100 years before the date of Black and White. Grimer supposedly came into existence as a product of post-industrial water pollution. If there are still new species appearing so recently in history, Mew can’t be that rare. But conversely, if they’re poorly adapted to almost all real environments, why are Mew still around at all? You know, there is that old line from the smug creationist, “if people evolved from monkeys, then why are there still monkeys, huh?” to which the answer, of course, is that people didn’t evolve from monkeys, they evolved from something else that is also an ancestor of monkeys but no longer exists, because humans and monkeys are both better at different things. If everything evolved from Mew, if every conceivable environment on Earth has some corresponding specialised form that works better than Mew, then why are there still Mew?
And the thing is, this still doesn’t explain the oddest thing about Mew – the fact that she supposedly contains the genetic code of every known species of Pokémon. We’re trying to see the variety of Pokémon that now exist as responses by Mew to specific environmental conditions – essentially improvisations – but Mew’s genetic library would then imply that all of those responses were predetermined, that she already had, from the beginning, every Pokémon’s form “pre-loaded” into her, by… Arceus, I guess? At which point, why do we even need Mew? Just say that every other Pokémon was created by Arceus ex nihilo. Which is why I always wanted Mew to be the “scribe of Arceus,” a being specifically given the supernatural ability to copy, store and preserve the DNA of other species, so that the genetic library is something she’s created over time through observation of every other species that ever lived. It explains Mew in a way that still allows something resembling real-world evolution to have happened. What I don’t like about it is that it more or less forces Mew’s role to be ordained by something, probably Arceus, and I am… less okay than I used to be with uncritically accepting that Arceus really is a literal creator god.
Something I think we often lose sight of, when we talk about her, is that Mew wasn’t even supposed to be in the game. She was something that Shigeki Morimoto slipped into Red and Blue literally two weeks from the games’ completion, using the 300 bytes of spare memory that were freed up after they took out the debug routines (which would be such a mad thing to think of today, continuing to make changes to the game after it was impossible to debug it). And the line about Mew being theorised to be the ancestor of all Pokémon isn’t even in generation I or any contemporary sources, as far as I know; I think it’s originally from the Silver Pokédex, and I think was added to explain why Mew can use every TM, potentially without anyone realising what it implies. Apart from my standard complaint that this isn’t how heredity works, it also makes things confusing for Mewtwo, because Mewtwo was supposedly created by gene splicing using Mew as a base… but Mew already has all the genes; there shouldn’t have been anything else to splice in (unless Mewtwo is somehow half human, which I don’t think is what anyone ever intended to imply). All of which is to say that I think it might even be a mistake to treat Mew’s lore as being planned or deliberate at all, as having any great significance for the Pokémon world’s history and cosmology. A lot of it was… potentially kind of ad hoc? Which I suppose is why I’ve historically been okay with throwing out the bits of it that don’t make sense to me.