The death of the brand doesn't necessarily mean the end of the bookstore.
(The RIM brand, for example, died last year but the company survives as Blackberry.)
The thing is that the brand itself is being tarnished by the struggles and controversies surrounding it. Like this:
http://www.hughhowey.com/does-bn-man...stseller-list/ http://www.thepassivevoice.com/05/20...ings/#comments)
So a potential buyer might choose to rename the ebookstore.
One possibility (teeth gnashing alert!) might see Nook become XBOX ebooks or (much less likely) get folded into Google Books or get bought by somebody else with their own strong brand.