A quote attributed to R D Feinstein RDF: No. There is no such thing as “communities” anymore. A person is perfectly justified in following his family’s Minhag. My question to the attributer Did you find anything on where the concept of a “family” minhag started (assumedly when the community one ended?) and who authorized the official end of communities?
I would have thought this was a temporary situation, rather than use the word “anymore”. We fled communities that had minhagim, and ended up in mixed communities that don’t have a single communal minhag. (With rare exceptions like the first half-century of Frankfurt-am-Hudson in Washington Heights.)
In general, minhag hamaqom takes precedence, but a new community that doesn’t have one yet follows minhag avos. See R Yochanan on Pesachim 50a, the beginning of pereq Maqom sheNahagu. See also the Shakh, YD 214 s"q 8.
But I think that’s all it is – an effect of recent remixing of populations. It took 5 or 6 centuries for Minhag Ashkenaz to coalesce from those of immigrants from various communities. You would think nowadays change happens much faster. But even “much faster” could be a far time away. But I am not sure equilibrium would be reached faster than then; the smaller world means a more constant influx of influences.
It sounds weird, but do you think 300 years from now, it will be significant to someone living in Qiryas York* that someone’s great-great-…great-grandfather (father’s line to 10 generations) was from Vilna or from Sana’a, Teiman?
And with things like Upsherin in the US, where I attened those made by families of Yekkish or Litvish backgroun. But then, I hope we’re not still in the Golah (nor in Galus) by the time there is a Minhag America.
Here in Israel, the coalescence is happening much faster: not saying VeShameru, or saying Ein keElokeinu daily, Haqamas haMatzeivah on Sheloshim, or Hilula every Yahrzeit (and I’ve also attended those made by people whose Minhag Avos is Yekkish or Litvish), etc…
* Qiryas York is my imaginary town, used in some bedtime stories. It’s a popular location for Kohanim and Levi’im who want a quick commute to Bayis Shelishi.