It's clear that Silicon atoms cannot be substituted for Carbon in our proteins, our DNA etc etc. But that does not mean Silicon cannot be base of some completely different life.
The main obstacle in my opinion is not only the fact that carbon is way more versatile in creating complicated structures, but also that it is way more abundant in the universe. For a silicon-based life to appear spontaneously, we would first need some mechanism creating planets with a lot of silicon and little or no carbon ... and quite probably "unnatural" concentrations of many more elements.
So maybe when our scientists master carbon-based abiogenesis in their test tubes, they may try to find out how to achieve similar outcome with silicon. But for now when it's not even clear what is needed for carbon-based life to arise from anorganic materials, it's a bit too early to try to construct it from silicon.