BS
There is no such thing as being too late to market with a unique product.
The problem was that they didn't commit to the vision of winphone7... all the core things people did with their phones were super streamlined and built-in.
Winphone8 stopped that and forced everyone back to apps... with the thinking that they would get updates faster. Microsoft should have published (or heavily incentivized) themselves, since attracting devs was already a tall order for a small marketshare phone.
Basically they broke their own feet, and then put their head in a noose... it had nothing do with "being too late"... you trend whore.