It's the only enterprise communications solution
BlackBerry's main strength has always been in the enterprise. It was originally a business-oriented product and grew gracefully into that market to become not just a market leader, but one that was respected throughout the industry.
With BlackBerry 10 the story in and of itself gets stronger. BlackBerry remains the only enterprise communications solution that is always connected behind the firewall, removing the need for VPN or complex authentication. BlackBerry Balance is unique within the market, an obvious win for people who use their phones for both their work and personal lives.
BlackBerry continues to enjoy loyalty coupled with natural conservatism/inertia that almost defines enterprise IT life. BlackBerry 10 is a product that serves this market well.
An uphill battle
It is tough to predict if BlackBerry can make a comeback yet, but with so many people bringing iPhones and Android smartphones to the office it is going to be a major uphill climb to regain mindshare. However, I agree with Matt that the conservative nature of business may be working to BlackBerry's advantage. I know many companies that are just now upgrading from Windows XP to Windows 7 so when BlackBerry took most of last year off, enterprise customers and IT departments may not have been that concerned. There is something to be said for the BlackBerry name and security so it is possible for them to have a comeback year in 2013.
Right now, iOS and Android have the smartphone mindshare and neither Apple or Google are going to sit idly by either. Some government agencies and large companies have adopted iOS and I highly doubt they are going back to BlackBerry until BB10 is proven itself. While I want BlackBerry to succeed as much as any other smartphone enthusiast, I have my doubts at this time.