Broadway musicals used to crank out hits. No more. “Shows just aren’t giving us any new hit songs. Sure, you can hear top 40 hits along Broadway. But the songs were composed 20, 30 or 40 years ago, and they weren’t written for the theater. Instead, they’re shoehorned into shows like “Mamma Mia!” (ABBA), “Movin’ Out” (Billy Joel), “All Shook Up” (Elvis Presley) and “Good Vibrations” (the Beach Boys). Next up is “Lennon,” which opens in July.”