The same reason Bethesda can come out with buggy, half broken mass adventure games every couple of years, the same reason we could move almost our entire manufacturing industry overseas, the same reason companies like Wal-Mart can pay their employees $8/hour and claim it's ok, and the same reason sports teams are allowed to tank their seasons.
Because people keep throwing money at these companies, and that's all that matters is that they keep making money on their garbage products.
Or was that rhetorical on your part?