I remember it happened once in 2011 (https://www.themarysue.com/price-bitcoin-falls-below-mining/amp/).
Satoshi thought and planned for it.
If the bitcoin price falls below the cost of mining, some miners will exit. It will temporarily cause block discovery to lengthen as the existing miners striuggle - but after 2400 blocks, the difficulty will adjust down. That means it's easier to mine. (The difficulty is directly linked to the cost of mining as you need many more miners to win a block when the difficulty is high).
Basically you'll get iterations of this till the cost of mining falls below the bitcoin price. If the bitcoin price fell to $1 I expect you'll be able to mine them with your laptop as the professional mining farms will have long given up.
Yet the opposite is also true, that is, if the price of Bitcoin makes mining "too profitable" then more miners would enter the market until the profit diminishes as is no longer attractive to new entrants. That is why I think that mining is interesting as an speculative way of producing BTC (or any other Alt) with sights set on the future increase in price rather than on the immediate profit.