Smart small businesses will simply try to be reasonable and ignore the more onerous parts (and especially the more onerous interpretations) of GDPR, correctly assuming that no DPA and no noyb-style NGO is going to come after them (and that if it happens, they'll likely get a warning, not a massive fine).

Meanwhile, big data companies are going to be prime targets, and will be forced to either change, or start paying a significant fraction of their global revenue in fines every year until changed or bankrupt.