Most mayor casinos have a 1x wagering requirement of your deposit before you can withdraw; few have a 2x requirement, but having a 5x wagering requirement is ridiculous and way too high. Casinos that do this will not gain a lot of traction as it is a lot higher than industry standard.
Wagering requirement for bonuses are indeed, most of the times, between 30x and 50x.
Anything above 1x wagering requirement for deposits is borderline unfair and gives the house a huge edge which is why such sites should be completely avoided so that they lower their wagering requirements in order to survive.
High wagering requirements for bonuses makes complete sense in order to ensure that they don't get abused.