Are removable batteries gone because of tracking reasons or cost reasons?

Look I get it, capitalist businesses only care about money and infinite growth, which is 99.99% the reason why removable batteries are a thing of the past, because they can manufacture phones for cheaper and it adds up when you're manufacturing thousands if not millions of phones. It also supposedly helps with water proofing but I can't confirm that.

But I seriously believe that these phone companies got pushed and incentivized by certain agencies to do away with removable batteries …

batteries businesses can care cost growth manufacturing millions money phones privacy tracking