It has never been impossible to run a company by injecting money into it to cover the difference between how much customers 'value' the product versus what it costs to provide the product. But the dot com days showed that without a point in the business model where the value exceeds the cost by enough margin to keep the business going, such businesses don't survive.
What neither Lyft, nor Uber, has yet provided is a credible 'size' at which they would be a going concern (covering all their costs), nor a really good idea of how being larger scales revenues more than costs in sufficient measure to become profitable.
I would love to see a document that describes the 'per driver' costs that these companies incur on a location basis (so costs per driver in Los Angeles CA, and per driver in Minot ND) vs revenue expectations per driver vs total available livery miles (how many people would have to want to go somewhere to support those numbers). Then you could at least see if there were any islands of profitability in that solution space.
So far, I've yet to see anything where the answer is net positive. Worse, any positive solution will be very fragile by definition because the barrier to entry is zero and so a third party can unilaterally drain profits out of a ride share company by starting up an unprofitable competitor and funding it out of pocket until it has done the required amount of damage.