> Russian and American behavior from a decade ago didn't (directly) cause that.

No, but it did cause changes that made it possible for people to change their habits when the current crisis hit them.

There was definitely a build up. Trump was held back from being Trump in the first term. Even with that, there was no recourse for any of the actions that he took. There were also the court decisions that happened in between terms. So this term, he naturally feels no need to hold back. It is unlikely this Trump term would happen had his first not happened.