Even Quantum Computer won't able to obtain private key of that address because it's public key isn't known.
My biggest question this is. Really we can't? Even if this is not possible in today's technology, what will be the future? I think there should be some progress on this issue.
ETFBitcoin just mentioned that quantum computers themselves cannot crack the private key which is why I don't understand why you are confused here. People assume that sophisticated technology in the future can somehow crack these addresses, but it is clearly not that simple.
Many BTC will stay lost forever unless someone finds a solution to this problem which is highly unlikely.