This is somewhat true, although a bit contextually inaccurate and not necessarily applied correctly; KenPom just recently wrote an article about this here:
Or since 1997, anyway
kenpom.substack.com
Purdue and Illinois did have the most efficient offenses in history, but the mean efficiency has also increased significantly as coaching has become more analytics focused, so further historical context is important. KenPom attempts to contextualize this by adding the delta to the mean efficiency (which for 2026 was 109.3). Illinois' AdjOE delta to the mean was +21.7, which is ~15th best since 1997 and I would say it still puts them (and Purdue) in the "historic" category. Adjusted for respective seasons' means, Illinois' AdjOE was still better than Champions like 2025 Florida, 2024 & 2023 UConn, 2022 Kansas, 2019 Virginia, 2017 UNC, 2016 Nova, 2015 Duke, etc....
Purdue's offense was more efficient than UConn's 2024 offense, even after contextualizing it historically. I'm not using better because it's too subjective. The difference here is 2026 Purdue wasn't great defensively. The offensive approach was entirely different for 2026 and 2024 Purdue so I'm not sure how you can correctly use them for comparisons.