Double Zero, in post 201 asks
As no answer publicly known - why allow similar a/c to fly ?
A less cynical response than that of Zorst in post 203 is that, a risk management approach to the question would first consider the likelihood of a similar incident occurring again in the timeframe required to determine the root cause of the accident.
Given the safety history of the 777, the length of time in service and the number of flying hours accumulated (even with the same type of engine), and the fact that this is the first time this has ocurred, the likelihood of the accident recurring in the next few months has to be extremely small.
Once more is known about the specific cause, then the risk profile will be reassessed.