Biden had the bureaucracy on his side (it’s well known that government employees are largely left-Democrats), so he was able to collaborate with it. In his first term, Trump learned that insiders were good at preventing him from accomplishing his goals when he ‘played by the rules’, so now he’s just ignored ‘the system’.

Insiders have plainly ignored the law in the past when it was convenient, (see all the agencies which violated notice-and-comment rule-making in the Obama years,) we’ve just never seen anyone ignore the administrative agencies to this degree before.

>In his first term, Trump learned that insiders were good at preventing him from accomplishing his goals when he ‘played by the rules’, so now he’s just ignored ‘the system’.

This seems obviously what happened, and it may be because of the unprecedented non-consecutive second term. I don't know if Trump's ideology has changed between this term and his previous one, but his tactics certainly have. He clearly came into this term with a plan to do a blitzkreig [unfortunate reference], to make changes at a rate and degree that would cut through all the bureaucratic obstacles he faced the first term.

And it seems mostly successful. The opposition, including many of the employees of the executive branch themselves, were mostly caught off guard. Over the last few weeks, it seems like they are finally starting to form a responsive strategy, and are pushing back more effectively through courts and public opinions. I expect much of this initial push to moderate, such as the tariffs, the funding cuts, but still with lasting changes. Of course, if any of the changes are found to be unlawful, they will get reversed. But that will potentially take years.