Why is Bitcoin’s mempool so quiet while its price surges?

The number of transactions waiting in Bitcoin’s mempool has been thin since mid-May, a rare event in bull markets. This prolonged quiet spell has pushed median fee rates down to 1 sat/vB or less, left many blocks underfilled, and revived long-term questions about the health of Bitcoin’s fee market. source: https://cryptoslate.com/why-is-bitcoins-mempool-so-quiet-while-its-price-surges/