Oh, yes, great a new dog!
Although I'm not sure if this is really a shift in target age, because if you have a look over the last 30 years there was a continuously improvement of details in accessories and figures (just to remember the introduction of figure imprints). And for sure this "slow" improvement gives PM a hight potential of releasing more and more sets within the next decades until reaching a full detailed real live model. If one set becomes "outdated" they just release it again, only with a few more details, and they are sure that the target age kids generation (respectively their parents) will buy it and the collectors anyway
I think this is not only a development that can be recognized in that kind of toys, but also e.g. in computer games: remember the early days with e.g. the Commodore C64 or Amiga computer games; they were quite simple and graphically not very demanding compared to nowadays standards. (Another totally different example is pop music: compare the generalized music from e.g. the 80ies with those hits from today: in a generalized view nowadays you can recognize that music titles have become "multi-layered" or "multi-dimensional" with a little addition here and some further layers there and another effert over there).
So "manufactured" things are going to improve constantly in lifetime.
Just me
on a philosophic morning