Where have all the guitarists gone?

Is the trend towards bands without both full time guitarists and bassists a reflection of the difficulty in getting enough good musicians to make up the numbers?

cf. Keane, Scouting for Girls, the Gossip, the White Stripes, Muse etc.

And if so, why? Are we seeing the after-effects of the dance music boom having turned so many potential guitarists into bedroom DJs? If so, the trend should lessen over the coming years as guitar sales have recovered whereas dance music and sales of mixing decks have had their peak.