No, Segwit has not been implemented.
Apparently you don't know the difference between the words 'implementation' and 'activation'. If you want to try out Segwit you can do so on testnet.
It has been merged, yes but the answer to my original question is that no one actually knows when it will be active. This is the real problem.
That's not a problem at all. You will be aware of the activation date once everything is ready and the appropriate version has been released. These things need not be rushed.