I think that speakers do experience some level of degredation over the years. I know my 12 year old vandersteens were starting to sound loose and 'chuffy' in the bass. This may have been due to my listening to more modern designs. I understand that speaker manufacturers have considerably better options for drivers and wire than they did ten years ago. I know there was a world of difference between my vintage vandersteen 2C's and the modern day 2CE signature. Same basic design, but with more modern components. On aging, speakers are an electromechanical device, and I know that there is a certain amount of 'flex' built into speaker cones. This is speculation, but it would seem logical that after a number of years these become more flexible and produce a less accurate sound. If your linn's sound great to you (which they should!), you should just keep them until you find something better. On the topic of 'home theater' speakers, there is some truth to the fact that a home theater designed speaker tends to be a little brighter and able to product the exaggerated special effects of movies. Way-overcooked bass being an example.
speaker degradation question
I know this isn't a brilliant question, but every salesman I speak to obviously tells me to replace my Linn Helix front channels because they are 8 years old. I burned them in properly and they still perform perfectly. I am told to upgrade because they were not designed for both HT and Stereo. Thoughts and suggestions appreciated, thanks.