Does halving compromise network security?

Call me noob, but there's something I don't understand about Bitcoin halving. Since all miners are operaring at marginal profit due to the difficulty adjustment algo that ensures that the cost to mine a block is roughly equal to the block reward, and since the electricity price and Bitcoin price doesn't change (at least not immediately), then effectively ALL miners will be at -50% income the moment the halving happens. Why would any miner keep mining? Unless of course many miners stop mining, which would mean it becomes easier to mine a block, so more chances to win the smaller reward for those who stay... But less miners means less network security, no? Until, of course, price goes up, so more hashing power gets poured in since it becomes more profitable.