This is a very bad solution, especially as share rides decrease the number of cars when people use uber pool
I think the implication is that people with cars keep using them and people without cars use Uber instead of alternative transport.
They're undercutting public transportation and traditional taxi services that need to operate with a realistic budget that isn't fueled by billions of VC dollars.
If they're undercutting public transport and doing so at a sustainable price, I view that as healthy competition. If they're undercutting solely based on VC subsidies, that will inevitably end. In the Boston market, I think they're likely profitable on an overall basis, just as grocers are overall (very slightly) profitable, even when they sell loss-leaders and give other subsidies to consumers.
Then you have maintenance, wear, healthcare, retirement, etc... Just accounting for fuel and maintenance these drivers are making minimum wage without any benefits, even if they drive full-time.
The so-called gig economy is bullshit that erodes just about everything it touches, from workers rights to public services.
I do think you really have to question an economic model where Uber/Lyft have clobbered cabs using an unsustainable VC-funded model that will eventually run out and substantially increase cost to the end-user.
Drivers who drive full time can afford to pay for the car expenses (variable and fixed). Drivers who drive part time are able to cover the variable costs (and they already had their fixed costs anyway). Uber is probably not losing money in Boston. If all three of those things are true, Uber is sustainable in Boston.