When asked about his biggest achievement and his biggest disappointment during his time at Microsoft, Ballmer explained that Microsoft essentially "created the PC," but he also went on to say that Microsoft doesn't "have as big a mobile presence as we need to."
Here's what he told CBS:
All along the way we've appreciated mobile, but we're not winning in mobile. There's a difference between saying "hey, you were asleep," and saying "hey, you didn't put the formula together right." We didn't.
Ballmer, on numerous occasions, said Microsoft missed out on the big "mobile revolution," which really kicked into high gear in 2007 as Apple and Google launched the iPhone and Android ecosystem, respectively. A major part of Microsoft's push into mobile - its $7.2 billion acquisition of Nokia's mobile devices business - occurred in April.
Nokia is currently the leading manufacturer of Windows Phone devices with its flagship Lumia brand. But the choice didn't come easily for Microsoft, Ballmer told CBS:
We had a lot of tough discussions about whether to buy Nokia. You know, it's a big decision for a company that's been a software company.
Ballmer was on board for the acquisition, and felt that current CEO Satya Nadella would be best to "really build this next generation of Microsoft that's all about the cloud."
Microsoft's emphasis on the cloud is more present than ever in new Windows 10 operating system. In fact, Microsoft says it skipped the number nine in its naming convention to emphasize that the next version of Windows will mark a new generation for the software franchise. On its official blog, Microsoft says Windows 10 was "built from the ground-up for a mobile-first, cloud-first world."
But, as Ballmer notes, Microsoft has been struggling in the mobile department. As of Q2 2014, the International Data Corporation (IDC) reported that Windows Phone only accounts for 2.5% of the worldwide smartphone market, while iOS accounts for 11.7% and Android accounts for 85.7%.
The chart below from the IDC shows how device shipments for different platforms have changed since 2011. Windows Phone as seen minimal growth, but still pales in comparison to iOS and Android.
For its part, Microsoft has made efforts to appeal to both smartphone shoppers and developers. Microsoft announced earlier this year that it's rolling out a universal app platform for developers, which means it'll be easier to create apps that work across Windows Phone, the desktop Windows OS, and the Xbox.
At the same time, we've seen a handful of updates to Windows Phone over the past year that add more functionality in areas where Windows Phone had previously fallen behind its competitors. This includes a new virtual assistant called Cortana and support for larger high-resolution displays, among other improvements.
But many popular apps are still released for Android and iOS long before they hit Windows Phone, which is part of the reason consumers are more inclined to choose one of those two platforms, as opposed to Microsoft's.
Check out Ballmer's full interview with CBS This Morning below.