There's essentially no cheap way to add anything to an airplane. Most changes will require extensive testing, verification, and sometimes certification when it comes to planes.
But anyway, where are you seeing a claim that it costs $100k to record and save turbulence sensor data? I don't see anyone upthread claiming that, and the article doesn't touch on it at all.
I read it in another article on the topic researching before commenting. Just didn’t bother to cite it but that was the official reason given as to why America doesn’t do this.
