When you look at first singles of albums since Pop, there is a direct three-way correlation between quality of choice of single to reception of said single to reception of album (critically, commercially or both).
Pop - poorly received, poorish sales, poor choice of first single.
Atyclb - greatly received, good sales, single choice was perfect, and received as the third coming.
Htdaab- greatly received, great sales, single received wonderfully well.
NLOTH - poorly received, poor sales, poor choice of single.
I think Pop and NLOTH are considered the equal, if not superior by the fans to both the others, but U2 need to start each album cycle with a song that resonates or the momentum is lost. If Pop kicked off with LNOE, or Gone, and NLOTH with MOS or Magnificent, we have two very differently received albums. Like it it not, the introduction matters with U2, mostly because the band is so polarising. To win the middle ground, they have to do it quickly.
Sent from my iPhone using U2 Interference
Good god, nearly 6 years between albums really is not good for the fandom. I just hope there will be some sort of news tomorrow, so the good times will be back. 
