No, the other settings caught on because of their quality and/or because they offered something new, not because they were attached to another property.
BTW they were
attached to D&D. As in, directly pushed by TSR. Greyhawk was drawn from Gygax's home campaign and then brought in as the first default setting, and then Forgotten Realms was heavily pushed by TSR as the new default setting to displace Greyhawk. Neither of them "caught on" organically because of their "quality" or because they "offered something new," but because TSR, who basically controlled the market, made a marketing decision to push them.
And both are very much fantasy pastiche settings, much like Exandria. So it seems strange to have so much beef with the CR setting for being unoriginal but then champion similar settings like Faerun, which didn't exactly invent the wheel. Let's face it, WotC's D&D settings, like most of its other tropes, are heavily derivative. And that's not a criticism; they are generic by design, to make room for plenty of different styles of DMing. I think it is a
strength of Exandria that it is often reminiscent of familiar settings. It's a familiar feeling D&D setting with contemporary sensibilities.
Your argument seems to be that these earlier versions of fantasy pastiche settings were better. I disagree. /shrug. Different people like different things.