The supply isn't reduced. It was the Bitcoins that were being mined that were reduced so, the main impact goes first to the miners. But you're right about the long-term effect of it that the price will significantly going to increase.

If that's going to be that long again then you'll be able to get through the next halving on 2028 and 2029 is likely the next bull run if we'll be basing it on the 4 year cycle.