That Lucky Old Sun is Brian Wilson's tribute to his favorite place on Earth: Southern California. This literal and metaphorical geography is a mantra to which he always seems to return. And that's not exactly a bad thing. It gives a sense of place, even perspective (each state seems to carry its own historical and artistic connotations, as Sufjan Stevens has demonstrated). Wilson does not lie about where he comes from, nor does he feel compelled, like Dylan and Stevens, to continually remake himself or try on different mantles of style and influence. Wilson is a workhorse for his idiom, which has always been a distinctly American one, rooted in the literal geographic—or in the case of SMiLE, historical—place. Old Sun is the distillation of this method. One could even call it a concept album in the tradition of Johnny Cash's America and Ride This Train (complete with the narrative interludes!).
This does not mean Old Sun simply rehashes more of the same, or treads the same water because it focuses on Southern California exclusively. In many ways, Wilson updates his style, while still paying tribute to the things he loves. The recurring title track describes the sun as a kind of bum who drifts around, just taking it all in while everyone else works hard in its glare. In many ways, Wilson associates his life (and art) with that of the sun. A large part of his laidback SoCal aesthetic is the ability to write about how great life is there, inviting outsiders to partake by proxy (despite Wilson's appreciation of regional women's particular "skills," he still wishes "they all could be California girls").
Part of the album's emotional tension, however, comes from Wilson's desire to associate with the lazy and forgetful sun's life, despite the fact that we know it's "the warmth of the sun" that allows Wilson to remember and create. This is the plight of so many artists: the desire to live in the beauty of moments while also expressing their beauty in a way that doesn't remove the artist from it. That is, how does one capture a moment without only appropriating it? This is the quicksand of art.
Wilson's greatest strength has always been his ability to express grief in the almost excruciating beauties of harmony. This aesthetic sentiment borders on religious at times (Wilson once called SMiLE a teenage symphony to God). Indeed, his ability with polyphony mirrors the greatest of the church's composers, Palestrina. Instead of melodic counterpoint, though, Wilson perfects the mixture of both melodic and verbal counterpoint that is the bread and butter of doo-wop and a capella groups. In the end, harmony is Wilson's means of drawing on the moment without destroying its integrity. Harmony does this by its natural (and historical) appeal to the transcendence of moments (it's hard to hear the kind of ornate polyphony Wilson employs without thinking of the religious worship) while still allowing them to exist as fundamentally sensory experiences, palatable to masses.
The fact that Wilson uses explicitly enjoyable music to express his grief allows many people to breeze over him and the Beach Boys as just more artists making ear candy. I still vividly remember the moment I realized "Good Vibrations" captures existential terror as much as it does the fun and mystery of falling in love (something Cameron Crowe exploited perfectly when he used the song in his film Vanilla Sky). The Beatles were doing something similar at the time, but never couched their dread completely in pop sentiment. There was always some self-awareness about their task ("Ob-La-Di, Ob-La-Da" probably comes closest, though the Beatles still can't resist their oft-used canned-laughter tracks). But even when Wilson is singing about his own personal history ("Fell asleep in the band room/Woke up in history") it does not come across as self-conscious, but just another California tale.