The combination of SSD + absolutely ridiculous efficiency sharing libraries on OS X, means that it's entirely reasonable to be running 25-30 applications simultaneously, including a VMware instance of Windows 7, All the Office Apps, Network Simulators, etc...
While there are obviously users that can use more than 8GB of memory (or heck, even more than 128 GB of memory) it's probably less than 1% of the Mac Using population that requires more than 8 GB of memory, and Apple expects that 1% to use the MBP. I don't think the Air will see more than 8 GB of memory for at least another 5 years.
yeah the 2GB part was a bit too much. Especially for Mavericks requirements (I was not aware).
My point is, with an SSD, you can swap, it won't be slow as the good old HDD days. On my workstation with 8GB of RAM and a 512 SSD (MBPr), I often have 8 or more GB swapped, it's not noticeable at all.
The only downside is that yeah, the VM file size will reduce your actual available disk space until you clean it up (reboot).
You completely misunderstand memory. 4GB is the bare minimum for Mavericks, any less and even on an SSD you're delving into swap hell. 8GB is really skimpy to have just as an upgrade option, I'm constantly hitting my limits on 16GB (though admittedly my workload isn't typical).
While there are obviously users that can use more than 8GB of memory (or heck, even more than 128 GB of memory) it's probably less than 1% of the Mac Using population that requires more than 8 GB of memory, and Apple expects that 1% to use the MBP. I don't think the Air will see more than 8 GB of memory for at least another 5 years.