Why does Microsoft not force Silverlight onto users machines through a Windows update?

Question

I'm not a Silverlight developer (yet) and what is putting me off - and many others, I think - is the relative lack of browser installations of it compared to Flash.

But I'm not clear on why website visitors have to explicitly install Silverlight themselves - which appears to be the major stumbling block.

Since the vast majority of computer users use Windows, is there a reason that Microsoft are not forcing Silverlight onto Windows machines through a Windows update?

They do this (and continue to do so) with the .NET framework runtimes, so why not with Silverlight? Legal issue, perhaps?

Answer 1

Getting sued by all its competitors is what stops this

Answer 2

There are several reasons why not to do it.

• Users should have choice over what gets installed. I realize from a developer standpoint we know some users who are clueless about what this software does, so why put the choice in their hands? Fine, MS should make it easy for users to install it if they don't have it when they visit a site that uses it. Then they can make an informed decision. Do I want to use this site or not?
• Corporate Approvals. Companies go through software validation procedures and that is why some will still be on XP for some time. If they were forced to validate these pieces because microsoft was forcing them down the pipe, they'd be pissed off. So thus MS gives corporations control over the windows updates that get approved/installed. And corporations are where MS makes their money.
• PC Manufactures choosing what software to preinstall. Here the manufacturers have the ability to push silverlight or not.
• Competitor's software isn't automatically installed. You actually have to install flash. Some PC manufacturers might bundle it with the PC but if you install yourself or for a corporate deployment, it isn't there by default.
• The monopoly power abuse concerns mentioned. But I think this is actually the least important reason.

Silverlight won't hit mainstream adoption till there is that one app that everyone must have that uses it. Like the office online example above.