Evidence from public markets and venture funding shows that the COVID‑19 shock and related capital‑market disruption in early 2020 were sharp but relatively short‑lived, and that fundraising conditions for startups were very strong well before 36 months had elapsed.

Key points:

1. Public markets recovered in months, not years.

   • The S&P 500 fell ~34% between Feb 19 and Mar 23, 2020, but then rallied quickly; by August 2020 it had already returned to its pre‑crash highs, and by the end of 2020 it posted a positive annual return of about 18%. (nasdaq.com)
   • This indicates that the capital‑market disruption tied directly to the initial COVID shock lasted on the order of months, not a multi‑year freeze.

2. Venture funding rebounded and then hit record highs by 2021.

   • Global VC investment in 2020 was on the order of $335–347 billion, only modestly changed from 2019 and still robust. (news.crunchbase.com)
   • In 2021, global VC funding almost doubled to around $643–671 billion, setting all‑time records; the U.S. alone saw about $330 billion, also a record. (news.crunchbase.com)
   • Reuters and other reports at the time describe 2021 as a record year for venture capital and IPO/exits, not a period of continued severe disruption. (news.crunchbase.com)

   For a startup that had 12–18 months of runway as of March 2020, its next raise would have fallen in mid‑ to late‑2021—precisely when funding and valuations were at or near historic peaks, contradicting the idea that they needed 36 months of cash just to survive a prolonged capital‑markets drought.

3. Contemporaneous VC advice centered on 18–24+ months, not 36 months.

   • Startup‑finance advisors summarizing VC guidance during spring 2020 noted that the pre‑COVID rule of thumb was 18–24 months of runway, and that in response to COVID many VCs began recommending ~24 months or a bit more, not 36 months, to bridge a tough year for new financing. (burklandassociates.com)
   • Sequoia’s famous “Black Swan of 2020” memo (March 2020) urged founders to extend runway and prepare for potentially difficult 2020–2021 fundraising, but did not suggest anything like a 36‑month minimum; the memo spoke of turbulence lasting “several quarters,” not three years. (cnbc.com)

4. Later downturns were driven by different factors.

   • There was another sharp deterioration in late‑stage tech and growth equity markets starting in 2022, driven largely by rising interest rates and a valuation reset, not by renewed COVID‑related disruption. VC funding fell from 2021’s peak but remained substantial in 2022–2024. (barrons.com)
   • Chamath’s prediction, however, was specifically about the duration of disruption stemming from the early 2020 COVID shock and implied that that same disruption would persist long enough that startups needed 36 months’ cash from that point to be safe. The data instead show a V‑shaped recovery in both public markets and venture funding by late 2020–2021.

Putting this together: a startup that entered COVID with an 18–24 month runway in early 2020 generally had access to exceptionally strong fundraising windows in 2021, and did not need to have 36 months of pre‑existing cash just to safely outlast COVID‑era capital‑market disruption. The prediction that “18 months is not sufficient” and that companies would “need at least 36 months” of runway due to prolonged COVID‑driven capital‑market stress is therefore not borne out by what actually happened.

On that basis, the prediction is best classified as wrong.