I don't think it's that deep. There's been no archetechual plans submitted for permits, etc. No firm has come forward to say "yeah, we've been working on this for a few months now" etc.  There's was no winterizing to fill the big hole in the side of the building. No security considerations for his protection by the Secret Service. 
Here's what I think happened- 2 days before he demolished the East Wing, there was the No Kings Protest. The largest single day protest in our history. It was was a protest against HIM specifically. 
He knocked it down in a childish temper tantrum. He destroyed part of an historic house because his feelings were hurt.