Plus miners are ready to run their machines for any job be it mining or hacking.
ASICs are built to do a single job. They cannot be repurposed to try to hack bitcoin addresses.
Couldn't that mean that if they make ASIC machines that are built to hack wallets, and what if it becomes a trend to hack bitcoin wallets and millions of people start doing it, and companies start creating very optimized hardware that their only purpose is to brute-force wallets randomly
There are multiple mathematical functions necessary to go from private key to "bitcoin address", so no, it would probably not be possible. It may *theoretically* be possible to create an ASIC to go from private key to public key, although there would not be a market for this type of ASIC because for all intents and purposes, the chances of one of these (non-existant) devices of ever finding a previously used private/public key paid is for all intents and purposes zero.
Brute forcing is very easy to code, however it is very computationally expensive. If you want any real chance of finding an already used private key, you will need to create an algorithm that is more efficient than brute force. However if you can do this, you will have broken secp256k1.