Apple intially exploited the loophole, which was ironically created to help them. But it was the EU that dropped the ball by letting them get away with it for so long. The entire saga is documented in the link below, which is probably best explained by this excerpt.

The EU's failure to regulate, in essence, provides Apple with an argument to keep their own solution.

For Apple, the common charger is a success story – of regulation avoided. For the next commission, it could serve as a cautioning tale on the limits of self-regulation.

https://euobserver.com/science/144538