I don't think churches are the biggest, most active community groups. Especially not where I live - the three churches each have an average congregation of about 20 - hardly active, or big. They do very little for the elderly, children, OAPs etc. unless they are members of their religion, which leaves out large numbers of people (from atheists, to sikhs, to catholics, for whom the church is only open one day a week) in the community.
Personally, I'd say the good local community groups are often schools, or charity groups. Indeed, in my local area I'd say the best local community group was the council - it puts funding towards numerous community events, from May Day celebrations, to a fireworks display on the river every November 5th, helps run community groups/centres for elderly people to meet, for homeless people to get help from charities, for single mums to get help in finding suitable employment etc. Groups like that, and other charities etc. reach a lot more people than churches, and unlike churches don't block people out based on their beliefs. After all, we're not all Church of England christians...
Also, what do you mean, a high % of Christians are called by God into caring professions? What about all the non - Christians who are nurses, care assistants, teachers, etc.? There are just as many christians as other people in the caring profession, so I'd say that statement of yours is rather lacking in truth, and undervalues what those non - Christians do.