OTT vs Telecom
In order to find an answer to this question we first need to understand how OTT works and how it is different from a normal telecom service. OTT rides on top of the data service offered by telecom service providers. It is almost like riding a wave driven/regulated by ocean currents. OTT has neither control over the structure of the wave nor can it regulate its speed. It is just at its mercy, and its ability to carry information is totally dependent on it. If the wave runs slow, so does the OTT voice, and he can do nothing to speed it up or alter its character.
On the other hand, the telecom operator is in full control of the wave. It can increase its speed, direction as well as thickness. Hence, at times when the voice service that the telecom operator offers gets impaired due to the quality of the wave (in the lift, basement, etc), then it (the telecom operator) has the power to kill the OTT voice just to make way for its own. This means at times of crisis, the OTT voice is at the mercy of the telecom operator, as he will and can do whatever it takes to preserve the fidelity of his service at the cost of that of the OTT player.
