I defy anyone who’s listened to Pink Floyd’s song “Wish You Were Here” to deny that at some point they’ve hummed, slowly rocked, or sung along to a lyric or two. It’s one of those melodic creations almost pure that fluoresced through the 1970s, simple in structure with rounded phrasing and punching dynamics: its whole as inescapable as the hearkening back to that epoch by some forgetting that the problems of today existed then too but in a different guise. The inability to escape. “Wish You Were Here” is a questioning song of life’s alternatives: heaven from hell, blue sky from pain, green fields from a cold steel rail, a smile from a veil. And it’s accusatory as it starts. David Gilmour sings, “So…