Here in Brazil my experience has been the same: drivers use all apps. I just don't see how Uber can maintain said network on the long run and still be profitab

Here in Brazil my experience has been the same: drivers use all apps. I just don't see how Uber can maintain said network on the long run and still be profitable, not something I'd put my money in. What Uber is doing would generally be described as predatory pricing on other sectors. On sufficiently unregulated markets such is Uber's it's extremely risky, no anti-trust legislation is needed to trump it, just a continuously low entry barrier, including lax regulation. For a more concrete, though only related example (rather than speculation as to Uber's future) see Dow's history.