BTC value has nothing to do with hashpower
Wrong,
- Some miners would be forced to shut down if BTC price crashed since cost to mine BTC is higher than earned BTC
- Big miners normally would expand their business (buy more ASIC) if they know it's profitable to do so
An example :
https://www.coindesk.com/bitcoin-price-decline-sparks-rare-mining-difficulty-dropan increasing difficulty and a reducing hashpower will also directly corelate to a decreasing supply for btc.
I think you meant slower block time due to decreased hashrate, but it's corrected every 2048 blocks.