>These laptops are focused on people who want to be able to do "everything" on a portable computer.
At some point when you are "doing everything" you start to be tied to a physical location anyway. Multiple screens, hook ups to external equipment. So it just doesn't make much sense to me to actually need to do everything in a portable manner.
Edit: Apologies, I didn't address the part about the Mac OS ecosystem.
This is for people who require portability epsilon percent of the time.
If you never require portability then a desktop is sufficient.
If you frequently require portability then it's worth getting an air and building your workflow (if possible) around offloading heavy computation to the network, e.g. heavy use of build servers, SSH, syncing.
But many people spend most of their time at a desk, but sometimes require portability. For example in a meeting, visiting a client, working from home occasionally, etc. For these people a heavy duty laptop is the best solution.
At some point when you are "doing everything" you start to be tied to a physical location anyway. Multiple screens, hook ups to external equipment. So it just doesn't make much sense to me to actually need to do everything in a portable manner.
Edit: Apologies, I didn't address the part about the Mac OS ecosystem.