WP 8.1 Developer Preview delayed again. Is Microsoft just incompetent?

This is now the second time WP 8.1 has been delayed. It's original launch date was supposed to come out in October 2013 as part of a yearly release schedule. Considering that WP8 was shipped with a lot of features dropped due to supposed "time constraints", at this point can it be said that the WP team is just plain incompetent?

Sure, WP launched later after Android and iOS, but BlackBerry (whose nearly dead), still launched a complete revamp of their mobile operating system in 2012 and has managed to stay in feature parity with Android and iOS. In fact, BBOS is about to receive announce another large update this week adding even more features, including a voice assistant. Microsoft has around 80,000 employees, and easily more resources and cashflow behind it, so what exactly is their excuse? BB has changed CEO several times like MS, has been strapped for cash and had to lay off staff, yet still managed to ship.

So what's the excuse?