Whether their calculations will pan out is another story. Whether such tactics should be allowed - yet another.
The Uber model is anti-econonmy-of-scale. It is a non scalable human wave approach.
For investors, the promise of profitability is continually just over the horizon, as long as you keep investing money. Everyone can see the company is potentially very profitable, but nobody can see a route there.
Though for the drivers, it looks a lot like a multi-level marketing scheme. Be your own boss, choose your own hours, work hard and you will be rich.
I always believe their intention was to become big enough and ubiquitous enough that they could become a monopoly supplier and therefore set profitable prices without the risk of being undercut, having consumed or removed their competition through subsidised rides.