[FabHK]

> new major airports for example Qatar Doha, US Denver and SA Upington has runaway length close to 5 km.

These are by no means average "new major airports".

Denver airport (from 1989) is the west's largest airport (by land area), and at 5000 ft+ elevation (necessitating longer runways).

Upington in the far North-West of South Africa was built in 1968 to accommodate a full Boeing 747 flying to Europe non-stop during the apartheid regime when sanctions meant that overflight or stops in the rest of Africa were not feasible. It has one of the longest runways in the world due to the use case and hot & high environment at 2800 ft (and was intended as an emergency runway for Space Shuttles, if memory serves correctly). It is hardly used anymore with less than 20 aircraft movements a day.

There is no recent trend for longer runways. The issue is extremely well known and well understood, by and large.