Because WebKit 2 isn't fully implemented yet is the main reason Safari isn't joinly leveraging GCD and OpenCL correctly across the GPGPU and CPU. OS X 10.9 clearly points to a massive improvement on both these fronts.
What kind of crap is this? Text editor vs. full blown word processor. That word processor dumps to hundreds of MBs in an instant when you actually use it more than typing a Dear Mom letter.
The memory is being stored due to the shared frameworks being pre-loaded. More importantly, those Core Data Frameworks are shared across the system of OS X. Please just stop while you're all behind in understanding shared resources.
If you think this product will compete with Apple TV then you don't understand the goals of Apple TV. Seriously, businesses are buying Apple TV systems for conference streaming events, multi-display Kiosks, etc.