As long as mining is profitable and the costs are reasonable, if we keep going like this then it wont last for another 8 years, imagine how many miners will be needed to mine by the next 2 halving? would you buy 100 ASICs to mine half a Bitcoin in a week?
Lots of people would buy 100 ASICs to mine half a Bitcoin in a week, if the price of one Bitcoin was $100,000...
It really all depends on the price of Bitcoin. Without the price rising, mining will indeed become less profitable. At some point there would be no more miners. We need to make sure companies continue to accept Bitcoin in order to grow the price at the same rate, or greater than the increase in difficulty!
But why keep the thing going with so much costs? one could fork Bitcoin(copy paste) it and start another coin, what happens if the electricity needed to mine half a coin was enough to feed a city for 5 hours then for 24 hours, do you really think people would go that far? I don't and I think Bitcoin needs to have it's own alt coins, built as layers on top of it and each requiring a different kind of hardware to mine, how are alts working right now, they are working right? now I'm saying lets have them for ourselves instead of giving this opportunity to shady developers to have their own coins, Bitcoin could turn into the mother coin only with nodes to validate transactions just like ETH, I don't know when Core devs and if they have any plans for this?