Because their business models and strategic positioning are different? If you are already packaging and selling a database during the course of your day to day business as carriers and credit card companies do, are part of an oligopoly leaving customers no choice, you don’t lose much by disclosing everything indiscriminately to law enforcement. If you peddle privacy in your ads and have a worldwide audience as opposed to US-only, you may have some interest in actually bothering to check a warrant for basic validity at very least, for example (even if it is just for show and marketing; this argument does not presume any sort of moral superiority, although I do personally believe that companies are not all created equal on that dimension either).

Also, empirically, I trust Apple and Google to keep data more secure from hackers than AT&T.

(I was also careful to use “blanket” requests as opposed to warrant in my original post)