Evidence from 2021–2025 shows that the privately led “space race” among SpaceX, Blue Origin, and Virgin Galactic has in fact produced major engineering advances and enabled new scientific work beyond the mid‑2021 state of the art.

1. Clear engineering breakthroughs

• SpaceX Starship: Since 2023, Starship—now the most powerful rocket ever built, powered by clusters of methane full‑flow staged‑combustion Raptor engines—has progressed from initial failures to a fully intact fourth test flight on June 6, 2024. That flight reached space, completed stage separation, survived re‑entry, and executed controlled splashdowns of both stages, a substantial leap beyond any capability that existed in mid‑2021. (theguardian.com) This is precisely the kind of large, reusable super‑heavy system Sacks was referring to.
• Blue Origin New Glenn: Blue Origin advanced from only suborbital New Shepard flights in 2021 to flying New Glenn, a heavy‑lift, partially reusable orbital rocket first launched in January 2025 and now with two successful missions. New Glenn can loft ~45 metric tons to LEO and has a reusable first stage designed for many re‑flights; the second mission in November 2025 both deployed NASA’s ESCAPADE Mars probes and achieved the first successful booster landing, a major new engineering capability for the company and for commercial launch options beyond what existed in 2021. (en.wikipedia.org)
• Deepening reusability across the sector: These developments—Starship’s large fully reusable architecture and New Glenn’s heavy‑lift, barge‑landed first stage—go significantly beyond the mid‑2021 baseline of Falcon 9 / New Shepard / unproven Starship prototypes, and they are explicitly motivated by competitive commercial goals.

2. Scientific and technological advances enabled by these systems

• Suborbital research (Virgin Galactic & Blue Origin): Virgin Galactic’s Galactic 01 (June 2023), its first commercial flight, was a dedicated Italian Air Force research mission conducting 13 human‑tended and autonomous microgravity experiments in biomedical science, thermo‑fluid dynamics, and novel materials, all using the suborbital platform that didn’t exist in operational form in 2021. (en.wikipedia.org) Subsequent flights like Galactic 07 carried a mix of private astronauts and a national agency researcher, again using the vehicle as a microgravity lab. (virgin.com)
• Blue Origin New Shepard science missions: New Shepard has evolved into a routine research platform: by 2025 it has flown over 175 scientific payloads above the Kármán line, including NASA‑sponsored technology tests such as precision lunar‑landing sensors and, notably in 2025, a flight that spun the capsule to simulate lunar gravity for about two minutes to test lunar‑surface technologies—something that previously required far more expensive facilities. (blueorigin.com)
• Mars science via commercial heavy lift (ESCAPADE): Blue Origin’s New Glenn has now launched NASA’s twin ESCAPADE orbiters, which will study Mars’ magnetic environment and atmospheric loss—science missions that, by design, ride on this new commercial, reusable heavy‑lift system rather than bespoke government rockets. (apnews.com) While most of the scientific results will emerge after 2025, the missions themselves are a direct outcome of the private heavy‑lift race.

Given these concrete advances—large fully or partially reusable heavy‑lift systems that did not yet exist operationally in mid‑2021, and a growing stream of suborbital and interplanetary science enabled by them—the prediction that this new privately driven space race would produce “great engineering and scientific breakthroughs” in the following years has clearly been borne out.