Assessment of the prediction
Overall, sacks’ prediction is substantively right, though somewhat oversimplified about which states were decisive.

1. “This is going to come down to Pennsylvania and Michigan”

   • Pennsylvania and Michigan were indeed central to the outcome. They were part of the former Democratic “blue wall” that Trump flipped in 2016 and Biden needed to win back. Biden did flip both states in 2020.(local10.com)
   • When AP and major outlets called Michigan for Biden on the evening of Wednesday, November 4 (the day after Election Day), Biden’s electoral vote total rose to 264, putting him “one state away” from victory and sharply narrowing Trump’s path.(fox17online.com)
   • Four days after Election Night, on Saturday, November 7, major networks and news organizations called the national race for Biden based on his lead in Pennsylvania and the remaining ballots there, explicitly noting that the outstanding Pennsylvania vote made it essentially impossible for Trump to catch up.(en.wikipedia.org)
   • Other states (notably Wisconsin, Arizona, Georgia, and Nevada) were also close and important, so it didn’t only come down to Pennsylvania and Michigan—but those two Rust Belt states were correctly identified as pivotal parts of Biden’s path.

2. “It’s going to take days to do those counts”

   • Michigan: Absentee ballots were still being processed into the early morning of November 4, and AP didn’t call Michigan for Biden until 5:56 p.m. EST on Wednesday, November 4—roughly a full day after polls closed.(local10.com)
   • Pennsylvania: Because of a huge volume of mail ballots and state rules preventing early processing, Pennsylvania’s count stretched over several days. Media organizations did not call Pennsylvania—and thus the presidency—until the morning of Saturday, November 7, four days after Election Night, explicitly citing the ongoing count there.(en.wikipedia.org)
   • Official certification in Pennsylvania was not completed until November 24, underscoring how long counting and canvassing continued.(inquirer.com)
   • So the prediction that counting in these states would extend well beyond Election Night was accurate, especially for Pennsylvania.

3. “We’re probably going to end up in the courts”

   • After the election, the Trump campaign and its allies filed dozens of lawsuits across several states, with Pennsylvania and Michigan among the most litigated.(en.wikipedia.org)
   • Pennsylvania alone saw numerous post‑election suits by the Trump campaign and Republican allies challenging various aspects of mail‑in ballot rules and counting; all were ultimately dismissed or dropped.(en.wikipedia.org)
   • Michigan likewise had multiple lawsuits filed to halt or overturn certification, including cases such as Donald J. Trump for President v. Benson and King v. Whitmer, all of which failed.(en.wikipedia.org)
   • At the national level, Texas filed Texas v. Pennsylvania in the U.S. Supreme Court seeking to invalidate the results in Pennsylvania, Michigan, and other states; the Court dismissed the case for lack of standing.(en.wikipedia.org)
   • Thus, the outcome was heavily contested in court, exactly as predicted, even though the litigation did not change the result.

Conclusion
Sacks correctly anticipated that:

• Pennsylvania and Michigan would be central battlegrounds in determining the winner,
• vote counting there would extend past Election Night by at least a day (Michigan) and several days (Pennsylvania), and
• the result would likely be fought in the courts, particularly in those states.

While the prediction slightly overstates that only Pennsylvania and Michigan would matter, and Michigan’s projection came relatively quickly compared to Pennsylvania, the core forecast matches what actually happened. Therefore, the prediction is best judged as right.