What is the actual profit of mining and how bad will halving hurt it?

So sure the price of btc is way up high but the "difficulty" and cost of electricity are also at all time highs. I had read somewhere that unless you can get electricity far under the going rate in the United States, It's not worth it to mine in the United States. With that said if the block award is cut in half, how many other places will become unviable for miners? Couldn't this cause a lot of miners to quit? the difficulty goes down when the hash rate crashes right? Doesn't the chain need a certain hash rate to not fall behind on ledgering transactions?