Bitcoin halvings are all set by Satoshi Nakamoto with Bitcoin source code. Two halvings will come to us after every 210,000 blocks that last about four years, a little bit longer or shorter depends on how 210,000 blocks found slower or faster than average block time of Bitcoin (10 minutes).

The key for Bitcoin growth is its adoption. With better, bigger adoption, Bitcoin will gain more interest in community and there will be bigger demand on Bitcoin. At the same time, total supply is not changed, it's always 21 million bitcoins. Circulating supply can be smaller with more bitcoins lost by careless people.

Basically with bigger demand, smaller available supply, its price on the market must increase with time. Bitcoin Spot ETFs, Institutional investors, politicians support Bitcoin, inflationary issues, etc. are different additional components for Bitcoin growth.