While American weapons do still top Saudi purchases, this is largely in brownfield weapons systems such as the F-15E [3]. For new weapons platforms, the Saudi Armed Forces have increasingly pivoted to Europe (Eurofighter) [4], South Korea (replace the F-15e's munitions and planes with next-gen KAI platforms) [5], and the PRC (UAVs and Cruise Missiles) [6]
In my opinion, all of this is due to Americans - both policymakers and voters - having Orientalist perceptions and stereotypes of the Middle East that are still stuck in the 80s and 90s and which has lead regional powers to hoof it on their own.
The old guard of Saudis who were extremely pro-American all passed away or retired from political life and the newer generation of Saudis have become increasingly disillusioned with the US. Also, the Saudi govt is stopping it's foreign scholarship program and so if you're paying out of pocket, European programs make more sense or Saudi universities which ain't that shabby anymore either due to extremely competitive hiring packages to EU and Asian nationals.
Addendum:
Totally forgot about the Fracking boom in 2014-16 causing a trade war between the KSA and USA [8]
[0] - https://www.wilsoncenter.org/event/saudi-arabia-and-the-iraq...
[1] - http://www.cnn.com/2003/WORLD/meast/03/18/sprj.irq.saudi/
[2] - https://www.jstor.org/stable/48673735
[3] - https://www.ainonline.com/aviation-news/defense/2015-10-06/u...
[4] - https://www.wsj.com/articles/saudi-arabia-agrees-to-buy-more...
[5] - https://www.tacticalreport.com/news/article/8047-saudi-arabi...
[6] - https://www.cnn.com/2021/12/23/politics/saudi-ballistic-miss...
[7] - https://www.politico.com/news/magazine/2023/02/03/pompeo-was...
[8] - https://www.reuters.com/article/us-oil-shale-kemp/is-saudi-a...