Sometimes secure-enough is all the security you need?
Of course, the only truly secure computer is powered off and buried 10 feet in concrete; that's been said since the very first computer. There's no such thing as 100% secure, so it's always true to say that "secure-enough is all you need." However, security is measured in degrees according to what you do and have access to, and most importantly security isn't something you add on later, like a bag hanging off the side of your device. Security *needs* to be built in to the original design.
The average worker usually doesn't have access to Strictly Confidential (read once and destroy) kind of material; they're not privy to the long-range plans discussed in meetings of the board of directors. So what device will the directors use? Android is secure-enough for whom? It's the directors, C-level, and upper management that use their devices in the most productive ways and they use far more than just email and attachments. We will still have the average user bringing their Android devices - albeit now with a built-in MDM app instead of the company-installed one - while management use their BlackBerry's; and we will still have a heterogeneous environment to manage and cope with at expense.
There's a H3LL of a lot more to mobile computing than simply email, if you actually want to be productive in your job. We need to stop thinking like average employees if we expect to be above average employees. That's where Apple and Android have failed to implement from the start in their design -- they built for the consumer, so cannot be truly corporate-grade until they redesign from scratch. You don't put airbags on a motorcycle and claim it's safe enough for your child seat.