This then charges L2 from the unregulated supply, which is used effectively as a switching mode power supply until the current across the 7805 drops sufficiently that it becomes the primary 5V ...

These two circuits provide ripple rejection for unregulated power supplies to audio amplifier applications and can follow a declining voltage source (such as a battery) to low values without dropout.

Asus has abandoned large enclosures for it's latest Thunderbolt 3 external GPU expansion case, with the new XG Station Pro separating the power supply's bulk and heat from the enclosure.

(Source: Lucasfilm) As described, a linear design is simple, reliable, and if an unregulated power supply meets your requirements, efficient, too. Add regulation, though, and the efficiency plummets.