Thats only true for the last 20 years or so of politics, traditional conservatives and modern libertarians (what I suspect people here are at least in part) believe the government should be small and stay out of peoples lives, whether it's keep your hands off my money or let me do whatever I want as long as I don't hurt anyone else.
Modern conservative politicians don't hold those views, but thats what being a conservative traditionally meant.
Actually, if you look at the history of politics in a number of countries (US, Canada, UK, etc.), the political right have always included those whose primary motivations are socially conservative, and who have sought to some degree impose conservative social mores through political means.
You are correct in that these groups have co-existed with the small-government conservatives (think the Red Tories, or at least some members of the Reagan Republicans during the 1980s), often rather uneasily (you can even see this tension within the Conservative party in Canada).
Libertarians at times were associated with these "conservative" groups, but they on average tend to be political independents, since they generally do not easily fit in politically to the right or left.
However, I would hardly say that "traditional" conservatives have never included social conservatives of what I just described. And in the US at any rate, the social conservatives have firm control of the Republican party to the exclusion of other political voices.
Samurai Joey