Just curious why this is or if there is a way to change this.
Thanks 
I kind of agree with @Mefistofel: it’s hard to organize complex meshes in triangle strips or fans, what makes simple triangles a better choice. Besides this, modern shaders usually spend much more cycles in fragment programs than processing vertices (this may not be true for a complex model at a long distance, but as said above complex models are hard to convert to strips/fans). By the time OpenGL was created, the available hardware barely could process vertices at decent frame rate, thus optimizations like triangle strips or fans could make a big difference, but with modern GPUs things changed so much that there’s a trend towards vertex proliferation via tessellation shaders.
Triangle strips are not used for three unique vertices(as usual triangle), they use one unical and two previous vertices from previous triangle.
To use this, you need collect special vertex arrays. They have a limited ways to use, such as to render the landscape (it is necessary to transfer less points - more polygons can be rendered).
For usual purposes such mode is not suitable.