I wasn’t claiming this was the only reason, just that it’s one possible factor. Here are some sources that highlight Russia’s role in supplying critical materials like palladium, titanium (via Kazakhstan), and nuclear fuel. While alternative sources exist, replacing Russian supplies isn’t immediate or simple.

Import Sources (2019–22): Palladium: Russia, 32%; South Africa, 31%; Italy, 8%; Canada, 7%; and other, 22%. Source: https://pubs.usgs.gov/periodicals/mcs2024/mcs2024-platinum-group.pdf

Palladium is critical to the U.S. economy and national security. Russia is the largest supplier of the metal to the United States. Source: https://www.usitc.gov/publications/332/executive_briefings/ebot_russia_palladium_and_semiconductors.pdf

Apparently there was no titanium sponge import directly from Russia since 2022 sanctions. However 9% of imports come from Kazakhstan (VSMPO-AVISMA subsidiaries) Source: https://pubs.usgs.gov/periodicals/mcs2024/mcs2024-titanium.pdf

US scrambles to break reliance on Russian nuclear fuel Russia had a monopoly on HALEU until recently. Despite U.S. effort to remedy tis issue for them their nuclear industry still faces challenges in meeting its HALEU needs domestically. Source: https://www.ft.com/content/7ead1252-70a5-4258-8d0c-b01a65bd61f1