It's not about going around and checking but being responsible about it. Thanks to GDPR companies do have someone designated to deal with these things and if they screw up and something bad happens they are liable.
Instead of developing operational excellence in their prosecution authorities to be able to track down and punish bad actors, they install regulations for everyone and try to simulate competence harming their own economy.
Not all crimes are preventable, which doesn't mean the laws aren't enforceable. Example: even though murder is illegal, people still commit murder, but they are rightfully punished for it, as the law mandates.
> [...] harming their own economy.
Do you have any proof that tech regulation is detrimental to the economy?