If no one mines bitcoins anymore, nobody can exchange them. Miners basically get a commission because they use their processing power to process transacrions between bitcoin wallets.
So, if no one is mining anymore, which is unlikely for now, you will actually destroy the currency. Even if it is still worth something, you won't be able to exchange it, so it is like destroying it.
I was thinking this then I thought 'imagine all miners quitting?' then I thought this is impossible, because if they quit I would start mining again.

To answer the OP, only satoshi has the power to destroy btc.