Reading a bit it seems to be potentially that the recommendations after the last big quake haven't been followed up properly. So basically stronger building requirements, with government validation was the plan; in reality not done (properly) and "checked" by paid companies.

Including how they handled the years up to the earthquake and how much corruption influenced the country's ability to improve their housing stock with respect to earthquake resilience. I think that's the main source of worry for Erdogan and his cronies. The 'building amnesty' was a clear bone thrown at business interests at the (literal) expense of the rest of the population.

Thousands of buildings collapsed killing lots of people inside them. Once the dead have been buried there will be calls for why nothing was done to improve the housing stock and in a de-facto dictatorship the buck stops with the dictator. Erdogan isn't going to be able to weasel his way out of this one without claiming another fake coup.

And that's before we get into the fact that for obvious reasons Turkey isn't able to handle the aftermath of this alone, and that makes Erdogan look weak. The fact that they are happy to switch off Twitter even though it is saving lives by allowing people to be found under the rubble is telling: even now the lives of the Turks matter less to the regime than their own image.