MVC is the worst way to develop applications, except for all other ways that have been tried. :-)
Joking aside, MVC is one application design that encourages us not to write spaghetti code. It's a guideline that reminds us to keep business code separate from presentation code. This is very helpful as the application gets more complex.
There are other variations that achieve that same benefit, but are not strictly the same as MVC. Presentation-abstraction-control (PAC) is one example.
As for why Microsoft is so late in adopting MVC, I'm not surprised that they are. They are pretty well-known (at least in recent years) for being conservative instead of innovative. They prefer to let other smaller companies take the risks in an unproven market, then they learn from the mistakes, churn out an overengineered competitor solution, and dominate through marketing.
Example: Microsoft Internet Explorer was considered to be a latecomer to the browser market. Netscape had become very popular, leading the way in providing a platform for people to view HTML. Once the amount of HTML content on the Internet was at a useful level, Microsoft belched up their onomatopoeic "IE" product and quickly captured an overwhelming market share.