As usual, Yogi Berra put it best: “Nobody goes there anymore,” he said of a once-popular restaurant. “It’s too crowded.” These days, it’s easy to feel that way about Picasso. For half a century, he bestrode the landscape of modern art like a Colossus, but that half-century ended half a century ago, well before his death, in the era when Minimalism, Pop art, Fluxus and the like were working (not necessarily with success) to cut the tense, taut cord that tied modernist painting to a longer, deeper tradition. Today, artists are more likely to claim a lineage from Marcel Duchamp or, if they’re trying to keep the former tradition in play, to see its main line running through Henri Matisse. Picasso, though he is still the popular byword for “famous…