(Foreward: Let me state here that I am sympathetic to the Original Poster's point. I am not using it to argue with the OP; I am using it to demonstrate why Network Effects matter, and thus those who think otherwise are wrong.
Behold, Network Effects in action!
This is the Second Order consequences of Network Effects.
The OP's claim is correct--technically--in that Meshi is a comedy derived from Wizardry, albeit at some remove, but the retort is the killshot: Wizardry is derivative of The Only Game That Matters.
So is Dragon Quest, the Final Fantasy franchise, Ultima (and its sequels), and so on.
The fact that Square Enix made their tabletop adaptation of FF14 as a Current Edition knockoff just adds to the evidence pile supporting Network Effects' validity, as if D&D being The Only Game That Matters for the entirety of the history of the Tabletop Fantasy Adventure Game hobby's existence wasn't enough.
Back around 2000, when Ryan Dancey originally explained Network Effects to people at RPG Net and elsewhere, using language much like I've posted here previously, one of the claims he made is that every competing product just ends up advertising the dominant player in the network and feeding into it.
Look above. D&D's Network Effect is so strong that VIDEOGAMES SEVERAL DEGREES REMOVED advertise for it!
This is why the only competition FOR D&D IS D&D- only its past editions and knockoffs are viable competition. Every other notable title is the D&D of its not-Fantasy niche, and all of them bow to The Only Game That Matters in turn. All of them, without exception, advertise for D&D. The same is true of every other market segment where Network Effects are primary; every competing MMO advertises for World of Warcraft, every competing tabletop wargame advertising for Warhammer, every competing CCG advertises for Magic (yes, including the all-digital ones like Hearthstone), every PC advertises for Microsoft, and every handgun or carbine advertises for Glock.
How? By being the standard against which everything else is measured. When you are the dominant player with the biggest network, you define what Is and Is Not for that segment, and would-be competitors find out the hard way just how strong that power of definition is when they try to square up against the Big Man.
Ah, I see a SMRT Boi in the back. You're asking how WOW beat EverQuest, right?
Okay, here's the answer: "We knew what EQ's most valuable customers wanted better than the company did, so we made the game that EQ's devs refused to make and sold it to them."
Compare Vanilla WOW--you can do that right now; go open a BattleNet account, download and install the BNet launcher, open up a WOW account, pay a month's sub fee, DL and install the Vanille Classic client, and log on--to EQ (it too is still online). You don't have to rely on videos or livestreams; you can experience the difference yourself.
That's how you overtake D&D: you have to deliver what the most valuable customers want better than the existing dominant player. Given Wizards of the Coast's position, that is not easy or cheap to do as a commercial operation; you need to not only have a product that does D&D better than Official D&D, but you need to get it out there and smear it into the faces of Normies near and far and show them how much more fun it is than what WOTC offers. It would help if you sold a complete turnkey product with no need for Endless Slop and instead focused your support on Social Media material teaching them how to use and master what you sold to them.
"But isn't that what the PDF merchants do?"
That's what they claim. Deeds, far more often than not, do not match words. If they did they'd be the Apprendice to WOTC's Master, and even then they still end up advertising WOTC's Official D&D because they aren't good enough. The way forward is to be so much better that WOTC (and everyone else) ends up advertising your product instead; you must become so superior that you become the standard against which all else is measured and thus defines what Is and Is Not.
"How will I know that happened?"
When you hear people stop asking the gaming equivalent of "Does it take Glock magazines?" and start asking "Does it take (Your) magazines?"
If you cannot achieve this effect, then you don't know what the target audience wants out of WOTC that WOTC is not giving to them. Until you do, you will fail; once you do, you will succeed with sufficient energy and effort put behind getting it out there and talked about- you still have to promote it.
That's why Network Effects are the thing that matters, and why even at some remove they do so much for you when you are the dominant actor- when you are the Master.
And that, returning to the top, is why the OP is technically correct and yet still wrong. Meshi is derived from D&D, and its existence (like Lodoss War, Grancrest Senki, and many others) advertise for it purely by being close enough for comparison. That is the power of Network Effects in action, and thus why it's a waste of time to be neither the Master nor the Apprentice; if you come at the king, you had better not miss.