Windows Program Downloads Being Huge

I have been using Windows line of Operating system all the way from Windows 3.1 upto Vista and now Windows 7.

(1) There is one thing I always noticed that whenever I downloaded a program for Windows from Microsoft its size was almost always huge for example recently released free antivirus solution called Morro was whooping 150 MB or so comparing it with industry leading antivirus software Eset Nod32 4 which is just 30 MB download; My question is that when all the things like required system dlls, resource files are present in the Windows system then Why the hack Microsoft's own program for Windows becomes so huge like Morro? Is it that They just package everything in it and re-invent the wheel and do not trust their Windows system installed at the user side.

2)When we install any new Windows offering it is almost always around 6 or 7 GB full install size. But when we install any Linux offering it is almost always 4 GB to 7 GB full install with all the necessary GAMES, OFFICE PRODUCTS, SYSTEM UTILITIES, NETWORK CONFIG UTILS, PROGRAMMING TOOLS ALMOST ALL, MULTIMEDIA PROGRAMS AND WHAT NOT - installed in one go and they are now industry standard and very usable.

when we spend say more than 300 bucks for mere BARE BONES SHELL of Windows which is always bug ridden and comes with a high requirements and there in linux world we get the whole world for peanuts, WHY? Why Microsoft is paying millions to a army of programmers who are always just churning out a barebones shell Operating system with mere Aero and glass effects thrown in? Where is Utility which we are looking for?