Microsoft Security Essentials must be a good thing
I think your comments about Microsoft Security Essentials are not particularly valid.
1. This is good press - with so many people thinking that Windows is full of security holes but alternative OS's are built like Swiss bank vaults - a positive story about MS providing FREE extra security can't hurt.
2. Manufacturers do have an incentive to provide Microsoft Security Essentials - it's an added feature that will cost them nothing - it could certainly sway consumers decisions to buy a system if they have added security plastered all over them.