The truth is actually stranger than fiction.
For HKIA to keep its ratings, the percentage of flights arriving into remote stands and disembarking without airbridges has to be less than x%.
Due to terminal congestion, more than x% of pax were using airstairs on remote stands and getting onto buses.
The solution, Hong Kong style, was to build a little mickey-mouse satellite terminal so the the pax can disembark on an airbridge, and then descend to ground level to get on to buses.
Welcome to Hong Kong, Asia's World City
They decided to develop T2 rather than the mid-field terminal, because HKIA wanted more land-side shopping (major business for HKIA), so they built a rather ugly mall with a few check-in desks and called it T2. You see Hong Kong has not really got much retail space
Looks as ugly as sin, and Sir Norman was not amused with the deviation from the master plan.