After almost 2,000 years the local churches that started out as geographically based entities have become many faceted things. I do not have to tell you how many varieties of Christianity, and what purports to be Christianity, there are.
At this time, there may even be local churches that are worldwide thanks to the Internet. Jesus told us that where as few as two or three believers are gathered in his Name he will be with them. He did not seem to limit his promise to any particular mode of being together.
Despite the many differences there have come to be in local churches, I believe the role of churches in Christianity has not really changed. I think they exist not for their own selves but to serve the people who are the body of Christ. We believers need to be supported, built up, comforted, loved, given opportunities to utilize our gifts, and receive much, much more of benefits to believers that can best be done in the context of a local church.
Near the beginning of the book of Revelation John is given a prophetic vision in the context of seven actual churches in Asia Minor. Great blessings are promised to people in the churches who persevere in their faith in Jesus Christ until the end of their lives on earth. However, the churches are told their light and lamp stand (there are various understandings of the symbolism) will be removed if they do not deal with various problems present in their churches.
It seems we have an obligation both to maintain our own faith in Jesus through adversity in our lives and corruption in our culture while also seeing to it that our churches remain holy and, to use an old expression “as pure as the driven snow.”