I agree with you that anyone using a Mac to get paid work done should either carefully research the software they need before switching or keep an Intel Mac around just in case. For most people with an Intel Mac from the last couple of years I don't see why they would need to buy an AS Mac on Day One. There are some people who probably should though such as software developers targeting the Mac Platform or planning to offer their iOS apps to AS Mac users.yes I understand all that. But obviously any person who rely on their computer to work with specific softwares would wait at least a few months for the major kinks to be ironed out; and make thorough research about what works and what doesn't. As for the plug-ins; it could take very long for them to be adapted; and I don't see an ecosystem with a mix and match of native/emulated plug-ins/apps working well if at all. Personnaly I use max/msp and ableton live in conjonction; plus multiple third-party plugin; and all of those have to be updated to work together; and I know for a fact at least one I rely heavily on will never be. I don't even know about the drivers of the many pieces of hardware I use. I don't even know about firewire compatibility if there is any. I suspect many people are in the same cases. Your mileage may vary but for me it won't even be an option for a very long time.
Anyone using only Apple applications can be fairly confident that they will work too.
Others should perhaps be more cautious though I do have a lot of confidence in the Microsoft Office team. Adobe I have less confidence in.