The long night of the living dead
MSFT can not be discouraged from these 'must have' ideas. 'Me-too' is the only motto they stand by nowadays. So Cortana will follow a growing line of useless implements that everyone has already been using for some time. Like Bing. Like Zune. Like Windows Phone. Like MSN (although that was once very popular), like the 'Surface'.
All these items have made barely a dent in the share of other things/devices in the market. Yes, some of them are very good, but they are ostensibly re-invented wheels.
Of course, things people really want like good Office on Android, Skype for business and Sharepoint that works have all only really just reached the market.
What next - a new Facebook?