"But Apple, stubbornly hanging on to its need to control the user experience, creates meshed hardware and software systems that deprive businesses of the flexibility to find the best balance of hardware, operating system and applications for the job at hand."
Good point, but only half the story.
Apple needs to control the I/O drivers as much as they need to control the user interface. One giant headache in MS world is hardware; specifically, drivers and integration. Apple doesn't have this problem because almost everything is truly plug and play. No drivers that I have to deal with; no funny business.
I just configured my daughter's brand-new MacBook, and hooked it up to the household Epson R340 with about 3 clicks in the Print & Fax control panel. No drivers that I needed to see. Clearly, there are printer-specific drivers buried somewhere in OSX. But I never saw them or any trace of them.
"After all these years, is there finally hope for Apple in the enterprise?" Actually, Apple's version of "Enterprise" has numerous advantages. The level of Apple-supported integrations means less integration and support by end-users and their IT departments. Yes, Apple products are more expensive, but this is only an up-front cost. If the TCO is going to be lower, so it is ideal for the enterprise.
I find the notion that Apple is depriving "businesses of the flexibility to find the best balance of hardware, operating system and applications for the job at hand" a little off the mark. In many cases, an enterprise has little or no useful concept of balancing hardware, OS and application. Many companies have default purchasing arrangements like Dell-Windows-Oracle, or IBM-IBM-IBM. Flexibility isn't helpful in these cases.
Indeed, the only time Apple's offerings aren't ideal for the enterprise is when we have the silly Tomorrow's Dollars Don't Exist ™ conversation. That's the conversation where the manager says the up-front cost is the only thing that matters, and long-term support costs aren't relevant. After all, long-term support is paid for in tomorrow's dollars, and we all know that tomorrow may never come.