The Bible is obsolete because the saner parts have been extracted and integrated into either the law system (e.g. the marriage system in the west) or education and social values, and have been refined other centuries of discussion and challenges to come up with a set of rules and principles that can work for our current population density and life style.

And in particular these rules and principles will continue to evolve, where the Bible wont.

What remains proper to the Bible are the funky bits, the outright offensive parts and anachronistic advices.