As the cost of energy rises, the energy to mine crypto rises, while the value of crypto keeps decreasing, I wonder if there's an inflection point where e.g. bitcoin just implodes and vanished because mining is losing money?

Bitcoin mining difficulty adjusts to the available mining power.

When price of Bitcoin drops. Some miners quit because it's no longer profitable for them. The ones that remain get more of mined Bitcoin for themselves so profitability of their operation increases. Difficulty of mining increases so that blocks are still mined roughly at constant rate.

Network can operate regardless of how many or how few Bitcoin miners operate.