Joe Biden did win the Nov. 3, 2020 U.S. presidential election, but the size of his victory was not "enormous" by historical standards.

Key facts:

• Biden won 51.3% of the popular vote to Donald Trump’s 46.8%, a margin of about 4.5 percentage points and roughly 7.1 million votes. (en.wikipedia.org)
• He won the Electoral College 306–232. This Electoral College margin is relatively modest historically and comparable to Trump’s 2016 result, which fact‑checkers have explicitly said was not a "massive landslide." (en.wikipedia.org)
• Several decisive swing states were very close: Arizona, Georgia, and Wisconsin were all decided by under 1 percentage point, with combined margins in the tens of thousands of votes. (en.wikipedia.org)
• Election analysts generally characterize Biden’s win as clear/decisive but not a landslide; it falls near the middle of post‑1960 presidential victory margins, not at the “enormous” end. (politifact.com)

Thus, while the prediction correctly anticipated that Biden would win, it specifically forecast an “enormous” victory—implying a landslide‑scale margin—which did not occur. The winner was right, but the predicted magnitude of the win was substantially overstated, so overall the prediction is best judged wrong.