Quality Settings automatic switch

hi all,
I was reading that article,because we have to be good looking on a wide panel of machines…

Big Bang Brain Games never went above 25 thousand triangles in a scene using 1-2 per-vertex lights and no pixel lights (essentially a VertexLit rendering path). Quality Settings were used to speed up performance automatically when frame rate drops. So on higher end machines a higher quality setting was used which had pixel lights enabled.

so my question is :HOW WOULD YOU DO THAT?

Ive never heard of that company before, i dont know what kind of games they create but it seems like 25k verts is nothing, in AAA games, the main character could hit up to 10k itself, scenes like crysis hit up to 650k i was told… So these game seem like nothing to me, what kind of genre are we talking about? Shooters? Puzzles? Kind of a vague question in my opinion.

MMO with shitloads of vegetation!!
is that possible to adapt the quality automatically with different machines?