Many of the greatest composers' greatest and most expressive moments involve at the crucial point a
turn. Where turns are concerned we think for instance of Bach, Liszt, and Wagner. But since around 1908 there has been a great paucity of turns and indeed consequently a great paucity of great and expressive moments in music.
Why do modern composers not realize how impoverished their technique has become in the absence of turns?
Turns such as you mention here are just one of so very many expressive devices in music that the suggestion that composers who don't use them in the way portrayed here are in any sense "impoverished" is, frankly, a nonsense. Not only that, the turn as was once denoted by a symbol above a note that was to be "turned on", so to speak, hardly died because composers largely ceased to use that symbol; think of the many so many examples in the music of the 19th century in particular, not least Schumann and Brahms - and, as an early 20th century instance, have another listen to
Das Lied von der Erde and its composer's slightly later Ninth Symphony or, as a late 19th century one, the inverted turns in the opening part of the "Hero's Beloved" section of Strauss's
Ein Heldenleben (and these are just a tiny number of cases selected entirely at random on the spur of the moment). I even use such figurations myself on occasion when the music demands it, but never notated with the turn symbol.