The 18–24 month window after early February 2023 (roughly Feb 2023–Feb 2025) did in fact feature very difficult operating conditions for many startups, matching Sacks’s prediction that it would be “pretty rough for a lot of companies.”

• Severe funding pullback and down/flat rounds. Global startup funding in 2023 fell to about $285 billion, down 38% from 2022 and the lowest level since 2018, with deep cutbacks at seed, early, and late stage. Reports explicitly note that 2021-era valuations did not hold up, and that many “promising companies raised flat and down rounds,” while startups had to tighten belts and focus on unit economics as investors deployed capital more sparingly. (news.crunchbase.com)
• Large wave of shutdowns (“mass extinction event”). PitchBook data, summarized by Business Insider and others, shows about 3,200 U.S. venture‑backed startups that had raised roughly $27–27.2 billion shut down in 2023, a pattern observers described as a “mass extinction event” for startups, driven by the funding drought and investor pressure to improve economics. (tech.yahoo.com)
• Widespread layoffs across tech/startups. Layoffs.fyi data, cited in major outlets, indicates roughly 450,000 tech layoffs tracked by 2023. Coverage in early 2024 reports tens of thousands more tech layoffs just in the first weeks of 2024, showing that staff cuts and restructurings remained common as companies attempted to survive the downturn. (en.wikipedia.org)
• 2024 still tough outside of AI. In 2024, global VC funding ticked up only slightly to about $314 billion, still ~55% below the 2021 peak, with nearly a third of all capital concentrated in AI startups and exits (IPOs/M&A) remaining sparse—evidence that most non‑AI startups still faced a capital‑scarce, high‑bar environment well into 2024. H1 2024 funding remained below or flat versus the prior year, and reports consistently described the broader VC market as subdued. (barrons.com)

Because funding contracted sharply, many startups endured layoffs, flat/down rounds, and shutdowns across exactly the 18–24 month period Sacks referenced, his prediction that it would be “pretty rough for a lot of companies” is well supported by subsequent data and reporting.