When I went 1×11 just after the launch of the M8000 XT, I found Evans were selling the XTR version of the shifter for less than the XT version. When I asked why, the chap serving me said that XT was currently the ‘must have’ groupset and was hugely popular, with them struggling to keep it in stock, meaning that nobody was discounting it at that point. Apparently most of their customers like to match components when something launches and would not consider mix and match, even if it was with a higher groupset.
I paid c£60 for my XTR shifter compared to the c£75 the XT was selling for everywhere else at the time