I very strongly doubt that they will be unable to profit. They've just managed to rack up so much funding without doing so that they haven't made it a short time priority yet. If they had no master plan for huge profitability only idiot VCs would continue investing.
Still, VCs can waste a lot of money on a bad idea with no real plans of revenue generation. Boo.com & Napster were both great examples who burned around $120m each (Boo's revenue strategy was apparently to spend $120m wooing big names in the fashion industry and throwing parties, whereas Napster's strategy was to spend $120m getting sued for enabling music theft).
