Lyft is being given a ~40% valuation premium over Expedia, with 20% of the sales and none of the profit (Expedia generated $842m in operating income last year).

What's the growth assumption on Lyft to justify the extreme risk imbalance in that equation? That they're going to do $15-$20 billion in sales within six to eight years? And that even if they manage to accomplish that somehow (while surviving Uber), they might only be worth then what they already are now as their growth inevitably slows considerably (removing the huge growth premium, contracting their sales etc multiple). It seems likely to end in disaster given the wild outcome required to justify the present pricing.