You should read the reports, and not news articles about the reports. These news articles are referring to the very first report, which made projections for the UK through October 2020.

Here's the March 26, 2020 report, covering the rest of the world, with far more specific predictions:

https://www.imperial.ac.uk/media/imperial-college/medicine/m...

In this report, they predict 2.2 million deaths in the US in the unmitigated scenario, and over 1 million in the "social distancing" scenario. Their projection if the US "suppressed" the virus (by uniformly cutting contacts by 75% as soon as the death rate exceeded 1.6 per 100k; by my math, that's about 5,000 deaths) was 474,000 dead.

So, uh...that was wrong.

They projected 40 million deaths, worldwide (current actual total 3.14M) in the unmitigated scenario, with between 1.9M and 10.5M deaths in the "total suppression" scenario (depending on how soon lockdowns occurred).

If you go to the spreadsheet [1], you'll see lots of other fun projections:

* 470,000-670,000 deaths in Japan in the "social distancing" scenarios (current total: 10,031, despite living mostly normally throughout 2020).

* 330k-740k deaths in the "social distancing" scenarios for France (620k-760k "unmitigated"; current total: just over 3M, despite a year of strict interventions).

* Let's not forget their projection of 60,000-90,000 deaths in Sweden, in the "unmitigated" scenario (current total: 13,968).

Overall, their predictions bear very little resemblance to reality.

[1] https://www.imperial.ac.uk/media/imperial-college/medicine/s...