They got compared a lot to the White Stripes - twin pillars of the rock revival and all that - but what got lost in that lumping together was the fact that White Blood Cells, the White Stripes "breakout" album, was actually their third album. Jack and Meg had been in the trenches for years, so when success came they had some anchorage - they kept evolving and moving forward in the way that they had already been doing. The Stokes found success right out of the gate. So where Elephant showed a pretty obvious next musical step (hello, guitar solos!), Room On Fire pretty much sounded like a copy of Is This It. Similarly, Contra sounds a whole lot like Vampire Weekend, to the point that one could plausibly argue that each band is not pushing their sound forward.
To which the question has to be asked: so what? Isn't the whole point of Vampire Weekend that people liked their music? And isn't that the kind of music that they want to play? So what's the problem? It's not as though the songs are different, they just sound pretty much the same. "Horchata" could have slotted in right past "Oxford Comma" on the debut album and no one would blink an eye. But somehow there's a sense that musical artists have to move forward or else they are somehow lesser.
I'd hypothesize that this has roots in the Beatles and Dylan, who both exert an outsize influence on the modern cultural perception of how a top-tier musical act should evolve. Both Dylan and the Beatles always moved forward, such that an early-period Beatles song like "Love Me Do" is almost unrecognizable as the work of the same band as something like "Happiness Is A Warm Gun". Similarly, Dylan was too restless to keep writing songs like "The Times They Are A Changing" for multiple decades, so even though his voice had a two-note range he still changed his songwriting style and overall sound around. "Like A Rolling Stone" would be the equivalent of Lil Wayne actually pulling off that hard-rock album he keeps hallucinating about.
But there's plenty of virtue in doing one thing and doing it well. The day AC/DC writes an acoustic ballad will be its last, and for that focus they've turned out a lot more classic songs than the scattershot Aerosmith. Bands that change and evolve can often evolve themselves right out of being any good. Just as Axl Rose. Or Rivers Cuomo. Or even Radiohead and Wilco, who evolved themselves right out of the sound of their best work (Being There/Summer Teeth, OK Computer).
Do I want Vampire Weekend trying to take a stab at their own Kid A? Not yet. Not until their twitchy preppy pop songs start to wear down, not until they hit their own particular songwriting wall. Premature evolution can kill a band just as surely as running in place can.
