whilst this reasoning is plausible it is also speculation, plusnet have never confirmed this as the reason.

It is also possibility related to the likes of talktalk stating BT's retails are loss leaders (and plusnet's published upgrades could have been evidence of that), but again this is speculation. Sadly it seems the timing of the announcements been stopped is too close to the performance drops.

Now there has been much made of as well with BTw's Manchester capacity issues, has this had a snowball affect to other parts of BT's network due to rerouting etc. (as people who have issues some are nowhere near Manchester), again who knows as we only get given droplets of information.

Would it be beneficial to let users know what the issue is and help placate people.

If you're delayed at an airport or train station not being kept up-to-date is very annoying.