Sure. Tail end of Obama, one term with him as president, one when they could finally investigate, indict, try, convict, and then have to go through a whole bunch of bullshit because of Trump v US, and then Harris. I mean, maybe it should have gone faster and I’m not particularly sure why it didn’t.

Looking at a gloss it seems like the answer is disagreement over what to charge exactly, collecting evidence, and changes in prosecutors causing some delays.

Decisions of the New York County district attorney's office?