On the contrary, the observation about background beliefs raises the burden on theists, because the Scientific Revolution shifted the background beliefs in atheism's favour.

Any assertion can be challenged. It's just that, to challenge you atheism, you now have to go through a whole lot of established science to get to it. What science did is it undermined anthropocentrism and the trust in intuition and authority figures, which were crucial for propping up theistic religions together. Now theists presume they have to compete on empirical, scientific grounds where their religion is doomed. Religions now are therefore emptier than ever. All it takes is the little boy to remind everyone that the emperor is wearing no clothes.