(To sum up the above) the ethnic monasteries as you noted are here for a reason (community, culture, etc.)
As westerners we should have the teachings in our own environments in order to develop community/attraction
Yes, that would be nice.
The Western Ajahn Chah monasteries have mostly Western monks (though, as I have said, ethnic lay support seems to be quite important), so that is one model.
As you have noted, there do exist places like IMS (and broadly similar insight places in other countries) that don't rely on ethnic communities. Which tends to mean that more of the expenses have to come directly from participants.
And don't forget the Goenka centres all over the world, which are mostly run by local people.
However, these (Insight/Goenka) places don't provide a monastic setting and don't often directly provide a "community" environment. There are, of course, various "insight" groups that meet weekly or so that provide some sense of community, and Goenka practitioners often have a weekly gathering. So some of that community thing is covered.
There are a variety of issues that one has to weigh up in choosing where to go for "live" interaction. For many of us there are choices between travelling infrequently to some other place, or being involved in a local community (monastic or otherwise) that may not necessarily be one's first choice, given different circumstances. For me, local community and teaching is important, and I attend the local Thai monastery and sometimes our local insight group. There are a couple of Ajahn Chah monasteries in my country, but quite far. If I lived close to one of them that's most likely where I would go (we have occasional visits from those monasteries, so I know some of the monks a little). Others in my city prefer the travel option to the local option. It depends on your priorities
In the end it often comes down to how much value one puts on being directly connected to a well-known teacher, relative to having access to a local community and good local teachers that no-one has heard of. Obviously a poor local teacher is not a good option, nor is a non-existent local teacher!. And, of course, there can be a combination of local community and occasional travel...
I'm sorry that this is getting us off topic, but my view is that there are actually a lot of local resources in many places. And working with those local resources may, in many cases, be a better option than wishing for a famous "brand" to arrive in town.