While I love my 24-105, I don't feel it, or any other L lens is required in order to get great results.
It's just required to get the best results.
I recently went to a wedding as a guest equipped with a T2i and a Rokinon 85mm.
While it may not be a low light king, paired with a fast prime it holds its weight just fine.
Sitting around $800 for the entire setup, being less than a single L lens, I consider the results peachy.
Of course it's all subjective; I've attached some downres samples.
While I understand the rant, I feel too much emphasis is being put on the equipment and not enough on the skillset of the photographer. I'm not familiar with the Pentax system, but it seems a flat profile could have made a world of difference. But then again, what do I know.