[Why is there no 4-year bull-bear cycle for BTC anymore?]
This needs to talk about the mechanism of BTC. The total amount of BTC is 21 million. Since the creation of BTC (2009).
Every 10 minutes, 1 block is rewarded, and 1 block contains 50 BTC. However, after every 210,000 blocks (approximately 4 years), the number of BTC rewarded per block is halved.
Approximately 2.63 million BTC was mined in the first year. About 10 million BTC was mined in the first 4 years.
Starting from the fourth year, because the reward for each block is 'halved', 1 block only rewards 25 BTC. At this time, only 1.3 million BTC is mined each year.
Then in the second four years, a total of 5.2 million BTC was mined.