Well, I take issue with a few points that have been made here:
-- I disagree that NLOTH is anything like Pop, or in any way a logical progression from it. First of all, Pop is clearly inspired by dance music, whereas NLOTH just as clearly isn't (okay maybe "Magnificent" at a stretch). Also Pop, is dark lyrically, whereas NLOTH is another "Let's all believe things will get better" kind of lyrical approach.
-- There are a lot of us (including me) who think that ALYCLB and HTDAAB are both better than either of Pop or NLOTH. I might argue that Pop's songs are as good as either of those records, but the execution of the record is the worst. Which brings to the next point...
-- Pop is clearly a more song-based album, whereas NLOTH is more an 'ideas' album. So, again, I don't much of a thread between them.
-- Given U2's apparent need to be larger than the Pope and The World Bank in global influence, it is frankly impossible to imagine them (well, Larry anyway) to agreeing to put out an ideas-album like NLOTH after a mild disappointment that made them temporarily less relevant, like Pop.
-- I'm also not yet convinced that NLOTH is the start of a "new era" for the group. Right now, I view it as an extension of where they've already been this decade. The lyrical approach is much the same as before, the production team is the same, and songs like 'Stand Up Comedy' and 'Get On Your Boots' are hardly groundbreaking. Anyway, it's too soon to judge this yet. We'd have to wait and see where they go next...