Let us hope that "ICT" is dead and buried
I have heard it credited to Kevin Riley of IMS GLC (though it may be wider practice) to say that you should first agree the definitions and then choose the terms. Instead of having a metaphysical discussion along the lines of "what does 'x' really mean", we should say "we want to discuss such-and-such, so what name shall we give it?"
So I agree with you that the terms matter only at the level of good marketing (itself not a trivial matter) - but the definitions are profoundly important in the distinctions and assumptions that they make. I think we are no more than a gnat's whisker apart on this.
On the comparative merits of "TEL" vs "education technology", I pick up on this discussion below, along with your PhD.
I too think we are pretty much in agreement ... The best labels to use is the main challenge ... As does the substantive point re the extent to which digital technology has changed disciplines. All interesting stuff which it is good to unpack/probe.
I will respond in 'manageable' (from point of view of my available time) chunks over the next few days ...