I've never been impressed with C.S. Lewis
That's one of the dumbest things I've ever heard. Of course that is not the "only logical explanation". In fact, it's a completely illogical explanation that's riddled with baseless assumptions.
Perhaps you just haven't learned to appreciate what you have. Perhaps your desires themselves are irrational and unrealistic. Perhaps you haven't fully explored all the wonders that this world has to offer.
Remember – this quote is from the most influential Christian apologist of the last century. Heck, the guy practically coined the term. Lewis was, ironically, a catalyst of my deconversion from evangelical Christianity many years ago. Even as a teenage Christian I thought his arguments were full of holes, and this quote is pretty typical on the absurd-o-meter.