Just like one clip of him botching something isn't proof that he's lost it, one clip of him nailing something isn't proof that he's still got it.
JLB doesn't need any defending. But the evidence is clear: on a night to night basis, and sometimes on a song to song basis, he is no longer what he once was, and any attempt to say claim that he is undiminished is futile.
BTW, no shame in not being what he once was. On any given night, he can be and is still fantastic. But he is no longer consistently great.