No miners won’t lose money. They will just make less money from mining blocks. It is by design. This is not the first time btc block rewards is getting halved so it is not going to be a problem. If I were a miner, obviously I would stop mining when mining became unprofitable. That’s how mining works. When you can make money, mine. When you can’t, stop. That’s the reason small operations don’t last long in this business. Big miners can afford to mine at very low prices because they invested in green energy but home miners usually pay too much for the grid electricity. In the end this halving come and go too just like the other ones before this one and miners that can mine will keep mining it.