I can imagine them being sick relying on unproven young goalies. Reimer and Scrivens are also talented guys, so was Monster, but that didn't work out at all last season. Acquiring Luongo wouldn't immediately make them a primary cup contender, but it will help them at least return to the playoffs and they know what they get. A goalie who backstopped a team to two consecutive President's Trophys, a narrow cup final loss, an Olympic gold medal and several more rounds worth of playoffs in the last few years. He might not be one of the god tier goalies in the league, but he sure as hell doesn't miss by much.
Yes, he is expensive and his contract is long. But I'd much rather fix the one huge problem the Leafs had for almost a decade (horrible goaltenders) than to invest the money into high class forwards and gamble on goaltending again. Just take one good look at teams like LA, Phoenix or Nashville and you see where a great goalie can get you. And if Burke can get rid of a few of the bad contracts (*cough*Komisarek*cough*) they should be able to afford at least Getzlaf anyway.