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?
Mining could maintain profitable or not. But the lasting time of bitcoin is not directly dependent on mining. The usage and demand are much more important.
Indeed. As long as there are users there will be demand and supply and bitcoin still lasts.
We never know when but bitcoin will lasts.