This doesn’t necessarily mean that Sony will only be selling flagship devices, as there will likely be budget-oriented X series devices. Sony may just want a unified brand for its smartphones and to focus on fewer, but better models.
The new X logo and brand will be heavily used in advertising and promotion, so it seems Sony is putting all of its mobile focus on this move. It could turn out well, especially since Sony is known for pumping out too many devices that are all too similar. Maybe we’ll soon see some truly great flagships coming from the company.