For Apple to overcome this ecosystem disadvantage, it needs to offer more than a better PC, which is what it does today. The apps won't follow until the installed base is bigger, but Apple could develop better corporate support, perhaps by leveraging its academic support model and bolstering third-party support firms. Even the Mac-loving IT support pros I know chafe at having to bring broken Macs to an Apple Store for repairs and find the difficulty of getting advanced information on new models a hindrance to planning. In other words, Apple lacks the support infrastructure that IT expects.
Add to this the fact that Mac OS X Snow Leopard didn't go as far to support IT needs as it could have, and you can see why some in IT continue to doubt Apple's commitment to business. For example, Snow Leopard's VPN support doesn't support the use of Cisco certificates, so IT has to manually configure each Mac. Snow Leopard's Exchange-compatible Mail client doesn't support multiple mailboxes or away notices. Snow Leopard's Boot Camp software, which lets you set up a bootable Windows partition on a Mac, couldn't run Windows 7 until Apple issues an update in January, months after Parallels Desktop and VMware Fusion supported Windows 7 in their Mac desktop virtualization environments.
Is the Mac glass half full or half empty?
With a few exceptions, the Mac is a better computer than a Windows PC. Users like it, as do developers and even many IT pros. Apple has done much to increase its fit in a Windows-dominated world, and the rise of browser-based apps and desktop virtualization software has eased the Mac's ability to fit into business environments.
But the Mac is still not interchangeable with PCs, unless you simply use them as Windows PCs -- in which case, why bother with the Mac? Passion for the Mac will continue to force IT's hand, at least for some users. What's not clear is why or how the Mac could be used as a default PC platform. Microsoft has been masterful at owning the core communication and productivity infrastructure in business, thereby keeping the Mac at arm's length. The cloud -- public and private -- could blunt that advantage, but not quickly.
The reality is that the vast majority of users work with Microsoft Office, and the irony is that Office is better on a Mac (thanks to a better UI) than on a PC unless you use its VBScript capabilities, which the latest Mac version doesn't support. So if it is just about apps, employees who use Adobe Acrobat, Microsoft Office, a browser, and email could just as easily use a Mac as a Windows PC. Those with specialty needs will typically end up with a Windows PC that can run specialty apps (except creative-services users, of course).