I heard that the reward is halved every 4 years after each halving, so the reward miners will receive will always approach zero. To maintain the Bitcoin network, the price of Bitcoin must keep rising infinitely, which is impossible. Could there be a point where the value of the Bitcoin miners receive is almost zero, and the Bitcoin network collapses due to a lack of miners?
First of all, we'll all be long dead before bitcoin approaches the zero-rewards era so for you (and us) this is just a theoretical problem. But in reality it's not a problem at all because, theoretically, at that point the miners would still earn rewards thanks to the network fees and the value of bitcoins should be high enough to sustain the mining costs.