Ayling is wrong in quite a few respects here.
A large number of transfer pax require a large number of flights to shift them through the hub.
This large number of flights translates into a large number of daily frequencies to key destinations - JFK being the ultimate example.
It's this choice of frequencies that makes LHR such an attractive O&D location for business. However, the business traffic would not on its own justify so many frequencies without switching to smaller aircraft.
Basically - you can't have your cake and eat it!