How have regulators not relaxed rules?

As I think about this, a few possibilities occur:

• The costs of lobbying regulators exceeds the costs of operating 18,000 flights. I find this ... unlikely.
• Lufthansa calculated that by not lobbying for relaxed regulations and flying to preserve its own slots, it could enter into a war of attrition with other airlines, some of whom would have to sacrifice their own slots. The more I think of this, the more likely it seems to me.
• The situation might have emerged over sufficienlty long time and with sufficient uncertainty as to not make the total costs clear.

I'd suspect that other major carriers might have come to similar conclusions and either not lobbied for relaxation or lobbied to retain slot-use requirements, again, for adversarial advantage.

I'm not sure what other explanations exist. I would expect that even "empty" flights would have had some cargo or similar component (training and flight-crew skills mainenance might be another benefit). But to the tune of 18,000 flights seems ... extreme.

@Gargron

Because only dictatorships put people in prison for things that aren't illegal?