Halving effect will not be instantaneous. Some expect that the price will take off at one time in half, but it is at least naive. Perhaps someone will be disappointed that it did not, and will rush to sell their coins. We can expect increased volatility. However, this volatility will be held, and the market budetet increase the deficit.
Why? Very simple. Demand will continue to grow and offer the extracted coins will drop by half. And never again will increase.
Here's what can be fun. Now every day is issued about 3,650 bitcoins. Simultaneously the number will be reduced to 1825 pieces. Given that the day runs about 250 000 transactions a total turnover of $ 5 to 15 million, it will create even more demand for Bitcoin, with such modest emissions.

Over time, the deficit will only increase. The complexity will continue to increase, but the reward will be reduced every four years.