Has BlackBerry finally reached the point of no return?Last week, news spilled out that Waterloo, Ont.-based BlackBerry is up for sale. Meanwhile, IDC reported recently that BlackBerry sales are down 12 percent since last year, while the new line of BlackBerry 10 smartphones has fallen flat.Exclusive: RIM CEO on What Went Wrong and the Future of BlackBerryFor large companies, though, this popular platform has a lingering presence. Many companies still use BlackBerry Enterprise Server\u2014in fact, according to BlackBerry, 90 percent of all Fortune 500 companies are still BES customers. This includes a wide array of industries, from Vivent (a home security company) to the U.S. National Weather Service to the University of Pittsburgh Medical Center (UPMC), as well as 1 million government and defense customers.Since the launch of BES10 in January, there have been more 19,000 installs worldwide, and 60 percent of Fortune 500 companies have tested the mobility management product. This past June, the company parlayed this widespread adoption: BES10 now works with Android and iOS devices.\n\nAnalysis: 10 Things BlackBerry Z10 Does That iPhone Can't\nCommentary: Why a BlackBerry Is Better Than an iPhoneAt the same time, there's something in the air. Market share has shifted to the iPhone and Android, the most innovative apps always seem to debut on the iPhone and the security landscape has changed. Even government agencies, including Immigration & Customs Enforcement and the National Transportation Safety Board, are dropping the BlackBerry for the iPhone.For anyone in charge of mobile infrastructure, there are several reasons to consider finally ditching BlackBerry for good.1. BYOD Makes BlackBerry Phones RedundantExperts say we are now in the age of bring your own device (BYOD), even if some companies have failed to embrace the concept. Gavin Kim, the vice president of NQ Mobile, a security company, says the shift in business occurred a few years ago. At one time, most business users had a BlackBerry. Now that number is down to about 10 percent, he says, compared to the roughly 50 percent of business users who now have an iPhone.Resources: All About BYOD Guide and Your BYOD Field GuideBES10 added support for other phones too late, Kim suggests. Also, competition from similar asset management and security platforms, such as the Samsung KNOX, make it harder to justify sticking with BlackBerry smartphones. 2. So Does Mobile Device ManagementMDM firms are also crying foul. AirWatch recently announced that Merck, the pharmaceutical based in Germany, had decided to ditch the BlackBerry in favor of Android and iOS models. The move was meant to increase productivity. Merck even has an internal enterprise application store for Android and iOS apps. Leading MDM companies are like the overlords of mobile infrastructure: When they start losing interest in a platform, large companies usually take notice and follow suit.3. Analysts Bullish About BlackBerry's FutureBusiness analysts have downplayed the importance of BlackBerry devices for the past few years. Roger Kay, an analyst with Endpoint Technologies, says the prospects look dim. While there are still BES users in every sector, the defections have started.\n\nNews: BlackBerry 10 Sales Figures Disappoint Analysts; Firm Asks for Patience\nMore: Photos of BlackBerry Z30 Emerge Amid Difficult Times for Smartphone Maker"They really have nowhere to go," he says. "The core value propositions of security and keyboard input has been negated by the other platforms."4. Innovative App Developers Eschew BlackBerryYou can still find basic business apps for BlackBerry; some, including Evernote, are even baked into the operating system. There are plenty of consumer apps for BlackBerry 10, too. But few innovative mobile app developers have even bothered with BlackBerry. Companies such as Zensorium, which makes a sensor for the iPhone, and Cue, whose eponymous app reads your email to help you manage your schedule, don't make a BlackBerry app because they know the market share has slipped. For business users, this means falling behind the latest trends.5. Security Innovations Erode BlackBerry's AdvantageSecurity isn't just the purview of large enterprise-grade providers such as Good Technology any more. The landscape has changed to include on-device protections such as face recognition (which is admittedly flawed) and complex passcodes.There are now hundreds of choices when it comes to protecting devices. Apps such as Cobra Tag can help you find a lost phone. You can enable full hardware encryption on an Android device before the OS even boots. Finally, Divide and other apps work well for separating work and personal files on iOS devices.John Brandon is a former IT manager at a Fortune 100 company who now writes about technology. He has written more than 2,500 articles in the past 10 years. You can follow him on Twitter @jmbrandonbb. Follow everything from CIO.com on Twitter @CIOonline, Facebook, Google + and LinkedIn.