Again it's the height of the holiday season both sides of the atlantic many/most businesses strategically avoid planned meetings this time of year as staff leave effects the office stability.
There are few conferences or trade shows now until September !
Bagso true some business travel takes place from the UK outbound on longer sectors from the Sunday afternoon but again many of those in the pointy end, traveling at weekend really are on subsidised tickets on one type or another including large numbers of "bribed" award claim upgrades.
Yields are often pretty poor and in many cases those in steerage are actually adding more revenue !
They also spend more at the airport in retail and restaurants than the lounge crowd !