PC's are no longer able to profitably mine BTC so people have stopped doing it.
Personal computer? Time will come that it will not be profitable but we don't have to think about it at this moment because bitcoin is still mineable.
What happens Antminers and the 'like' can no longer mine.
Manufacturers will just build another hardware just for mining bitcoin.
I know that there might be some new device being built that will be able to mine it, hower it seems that the hashing power needed is rising faster than the technology needed to solve it is becoming available.
Then they will just upgrade the current hardware as technology is rising too, so there's nothing impossible now.