I do not understand then, why whole crypto industry is in fear of an arrival of quantum computers?
Because they are fearmonger. 
Joke asides, it's because when Bitcoin started in 2009, Satoshi chose to make the coinbase transaction payable in public key. The uttered “Pay-to-public-key” (P2PK). As a result, thousands of addresses containing this unspent output of 50 BTC have exposed their public key.
Besides that, every address that is reused has also exposed its public key. Currently, the one with the most bitcoins, Binance's, has revealed its public key.