I realised one day that, when I was talking about myself (a rare occurrence ;-)), I was now saying "I have lived In Prague since ..."instead of the "I have lived in Prague since ..." that I had previously said. Prague had become my permanent home.
So, I agree - to a degree. I am fairly sure that I still use the progressive form at times, and I also believe that I used the non-progressive forms in the days when I knew that I would leave Prague (as I did) with no plans to return. My point is that I think that when the idea of permanence is uppermost in my mind I use the non-progressive form; when the idea of limited duration is uppermost, I use the progressive form; when neither idea is particularly strong, I may use either.
I discussed this with colleagues in the past, and some, at least, felt the same. We seem to have a tendency here rather than a rule .I'd say that, when there is no clear context, then the progressive and non-progressive forms appear to be interchangeable, with no real difference in meaning. This is especially true of verbs that frequently carry within themselves a suggestion of a longer action, state or process, e.g., live. stay, work.
I am talking about situations that began in the past and extend up to, and probably beyond, the present moment, often with since and for. In other contexts there is a fairly clear difference:
I have been writing a letter. - There is no indication that I have finished it - indeed, I quite probably haven't. Context will make this clear, if it is important.
I have written a letter, - I have definitely finished.