Ah, right, thanks! So old wall warts were like the power supplies the OP describes right at the start, and the change we've is that newer wall warts are like a scaled down version of the ones he spends the rest of the article describing.
And I would add that switching power supply tech has been around for decades (hello, desktop PC tower cases!). It just wasn't used as often in consumer devices because they were more complex (more parts, trickier to design) and
there simply weren't many consumer devices around that required so much power _and_ portability.
I would argue laptops were the killer app as far as switchers are concerned. Once they showed up and got popular, designers newly had reasons to design switchers more often.
A lot of the old wall warts are "Type 2", which means transformer, rectifier, reservoir capacitor -- no regulation there at all. With light or no load, the output voltage can soar (such as, 18v DC no-load from a nominal 12v DC @ 300 mA wart). The switchers are regulated, so you get what it says on the tin.
