Before Macs switched to Intel Microsoft bought VirtualPC from Connectix and basically let it die a slow death on OS X, but then continued developing it for Windows. When the switch to Intel finally occurred, and MS could have followed in the footsteps of VMWare by releasing virtualization for Intel Macs, they instead almost immediately made a press release on the death of VirtualPC for Macs.
The same is true of Halo, that was originally a Mac-only product. Rather than continue development on both platforms, they ceased all development on OS X; the X Box saw Halo before Macs did. Two years later they finally licensed it to Aspyr to do a Mac port.
When they decided they wanted Word to overthrow Word Perfect for DOS/Windows many Mac users will remember the release of Word 6 -- a revision so terrible that it couldn't have been coincidental.
There's other examples probably I'm forgetting. Skype is a very appealing reason to own an iPad, and strategically it makes perfect sense for MS to kill it on every platform but a their own. The Linux version will be the first to go, since they'll never get over an open source product dominating 60% of the server market they wish they had.
The Microsoft MacBU only exists to 'prove' they are not being anti-competitive; the only product they produce is Office. Each year after about 2004 (when the switching phenomenon started to occur) they dumped one or two Mac products each year.
If I gambled I would put $1000+ on the table about everything I wrote above. They will come to iOS only when the writing is on the wall for Windows 7 Mobile and even then maybe not.
