The chief responsibility of a Wikimedia chapter is to promote and pursue Wikimedia interests specific to its country, and as a practical matter often its entire region. This includes mobilizing local members of the community, but also a multitude of other projects that simply aren't within the scope of the Foundation.
The latest report of Wikimedia Serbia's activities came through my inbox yesterday, and it's amazing how many unforeseeable things come up. They handle them all, however, and so far quite well. The eclecticism of an organization such as this makes it difficult to define a specific scope here and now, but let me address your points in particular:
"Fundraising" in a chapter context means several things:
* The solicitation of grants and sponsorships in chapters' respective countries * The collection of money to maintain their organization and fund their own initiatives * Proxy solicitation on behalf of the Foundation, a tricky legal issue
Managing donations for the Wikimedia projects will always be the purview of the Wikimedia Foundation.
It's true that one of the traditional roles of a local chapter, liaising with local organizations and government entities, is a role currently handled by the Foundation, and one an American chapter needn't and perhaps shouldn't replace (or even become involved in). It's not an all-or-nothing issue, however.
Local hosting isn't a chapter matter, except perhaps for facilitating donations of hardware and/or rackspace. Currently, all such donations are agreements with the Wikimedia Foundation itself, managed by the Wikimedia server admin staff. This could change in the future, but it's hardly the killer app for any chapter.
Austin