We’re making it as easy as possible to get Windows 10. Windows 10 has been designed to run well on today’s Lumia phones. Like any upgrade to a new platform, not every phone will upgrade or support all possible Windows 10 features, and certain features and experiences will require more advanced future hardware. Our goal is for the majority of the Lumia phones running Windows Phone 8 and 8.1 to join the Windows ecosystem along with an expected hundreds of millions of PCs, tablets and other devices running the next generation of Windows.
Instead of answering the question with “Yes”, it goes in a round about manner to explain that not all devices will get the same features and that the goal is to get the majority of wp8/8.1 Lumia phones to join the Windows ecosystem running the next generation of Windows.
Perhaps it just means they want those users to get the update to W10 vs the possibility of update? (i.e. Windows 7/8.1 users CAN update to W10 for free but will they). With the “not every phone will upgrade” is that the likes of Lumia WP7/7.5?