Unfunny and unpopular are not the same thing. A show does not stay on air for 12 seasons by being unpopular and unfunny. Producing television is expensive, and networks renew shows because they are profitable and have strong audience demand. The Big Bang Theory may have been disliked in some online circles, but commercially and mainstream-wise, it was clearly a very popular show.

CBS did not keep funding 12 seasons of a money pit out of the kindness of its heart.