And there you have it - you just talked yourself out of solar-based energy as a viable replacement for all of our energy needs. If we're currently around 30% in efficiency, then we can only get a maximum of 3.33x better, but we're orders of magnitude away from viability. I'm not sure what other analogies I can use, but it's like you're trying to fill a swimming pool with a teaspoon and saying, "gee, if I only had a TABLESPOON (3x bigger), we'd be all set."
I assure you that this is not my problem with understanding solar - I'm one of the industry experts that the USAF turns to on matters of thermal efficiency in new aircraft designs. The problem is that we ARE close to the maximum efficiency - we're "only" 3x away from the absolute peak efficiency, but solar radiation is ~1000x too diffuse to be viable. Play around with the efficiency all you like and we still wouldn't get there. The problem that most people who favor solar have is that they usually only focus on replacing electricity generation (not total global energy usage), so they're only looking at a rather small, relatively easy part of the global energy problem - solar can't begin to scratch the surface of our current reliance on petroleum for transportation (land, sea, and air).