A: Dr. Fletcher put this point across very differently a couple of years ago.
B: I don't think so. He's given the same lecture for the last ten years, without changing a word of his script.
A: Dr. Fletcher needs to update a few points in his standard lecture.
B: Yes, he's been giving the same lecture for the last ten years. He really needs to do something about it.
No. Neither of them, by themselves, mean that he's going to stop giving lectures.
What made you choose the perfect continuous over the perfect simple in one of the two, and the perfect simple over the perfect continuous in the other? I don't see this difference, I'd probably use the perfect continuous in both.
I once asked a British friend of mine, who taught English for four years in Minsk (now he's in England), what's the difference between the perfect simple and the perfect continuous
when expressing duration up to now, and what's the difference between the past simple and the past continuous
when expressing duration in the past, and he said that they are all fine (with action verbs), it's just that the perfect continuous is more common if it's until now, and the past simple is much more common if it's in the past. That looks like a reasonable, valid yet simple explanation.
I
've been do
ing it for five years (since 2018). -
more common
I
've done it for five years (since 2018).
I
was do
ing it for six years (from 2009 till 2015).
I
did it for six years (from 2009 till 2015). -
much more common