The largest factor in phone security is the ability for the vendor to own the hardware to software soup to nuts. This is technically available for Android and iOS since Android is a fairly open source software and iOS is built to spec on hardware defined by the same company. So why the giant AD for CES?
As pointed out in the comments and other answers, Apple has done a great job presenting themselves as the most secure platform. The encrypt a lot of their phone data. They don't sell your data. They hardly track anything at all in fact. They also have the capability of building physical security controls to prevent the exploitation of their software (see GreyKey).
Meanwhile, many android developers have taken a different approach to the phone. Many companies have chosen to sell the best features or lowest cost devices they can to saturate the market and earn their pretty penny. Especially on lower cost devices, of which Android is majority, you can bet your life on manufacturers skipping corners especially in way of security testing and hardening. It's not that they couldn't, it's that they don't for cost or profit reasons.
Going beyond the generalized statements, there are security focused android devices as well. Google has been one of the leading developers of user identity management and security, working to build into their products physical security controls just like Apple has. HTC recently developed a phone that has a security enclave to protect cryptocurrency wallets and prevent wallet theft.
In the end, it really is more publicity/marketing than hard facts. Android CAN do everything iOS can do; the real question is if ZTE/Huawei/Samsung/LG/MOTO and others are willing to step up to the same bar of both physical and software security. And in my humble opinion, most probably wont.