You're right. Startups are overvalued. But they're still making money. The Indian 'unicorns' - Flipkart, Snapdeal, Ola, etc. have real revenues and customers.
Do they deserve their $1Bn valuations? Probably not. But do they have enough customers to give them $100M-$1B revenues? Yes.
If these startups were public companies, they'd still be valued at at least half of what their last Crunchbase entry says