Harry's explanation was one that clicked - I hadn't thought of the wifi issue.
There's no user replaceable battery in it, sadly. I think I'd probably buy one second hand if I broke this one - however if the battery went I could most likely open it up and find an exact replacement somehow. My worry is accidentally breaking the screen.. of the 3 Cybook screens I broke one was when I fell asleep reading it, and my leg kicked when I woke up, sending it flying across the bedroom to smash. The other two broke by torsion. The one that sticks in my mind vividly is when I finished reading it in a cafe in Florida, closed the case up, put it in my pocket and walked back to the condo, took it out and it was broken. Inside any decent case it's as protected as it can be from impacts, however uneven pressure or twisting, unless the case is rigid, will apply pressure to the plastic case which will bend, and when it bends past a certain point the glass inside will shatter. Considerably more force would be required to contort a metal shelled reader to that point. Before I flung one of the Cybooks in the bin I decided to see how easy it was to damage. I took my thumb and index finger of each hand and placed them on opposing corners of the Cybook and twisted. Not much pressure at all was required to cause further damage to the screen. Clearly I'm going to strongly suggest that people take my word for it rather than try to prove me wrong, but if you have for some reason an old device that is going to be destroyed anyway, grab the top and bottom of it with your hands and twist, the screen will break.
It's also possible it was a design issue unique to Cybook Gen3s. Perhaps other readers in plastic shells are more robust or lack a design flaw which leads to this. It's not a very easy thing to test.
The flexible screens have been on the cards for years now, the Readius was supposed to have one, and then I saw a youtube video of a screen being battered in 2010 and not breaking. That's my best hope I think, that by the time my 650 shuts down for good there are flexible displays available.
All things considered though it looks that prices are heading downwards, so it's not the £200 nasty surprise when the screen breaks these days.