yes that is very right. the number of bitcoin users are increasing too much and that is the reason that the supply will decrease and so the price of bitcoin will increase as no one is welling to sell their bitcoin.
Only the block halving makes sure that the supply reduces every 4 years, and not the increased number of people finding their way into the Bitcoin world. Less supply means less pressure on the market/price. Block halvings are meant to prevent long periods where there is more supply than actual demand, that eventually will result in a lower price.
That is the good side of bitcoin halving which it lessen the supply of the bitcoin but in the other hand it increases the mining difficulty and also halves the block reward for the miners which it makes it harder for them to earn decent profit and can be a reason why other average miners abandon mining or supporting bitcoin because of low profit.