Alkaline batteries definitely last longer than zinc chloride batteries. The difference is much more marked in where high current drains exist. (e.g. you won't notice that much difference if you put alkaline batteries, instead of zinc chloride ones, into your TV remote control or a 'conventional' radio. But there's a much bigger difference if you put the batteries into something which draws a high current, such as a remote-controlled model car, a DAB radio or a digital camera).
At one time the only widely-available brand of alkaline batteries was Duracell, so it was reasonable to claim that Duracell batteries would outlast all others. These days there are many other brands of alkaline batteries available (such as supermarket 'own brand' batteries) and there's probably very little difference between the brands.
That assumes that you're actually comparing 'like with like'. Most manufacturers (including Duracell) now offer more than one type of alkaline battery, with the more expensive types being specifically designed to last longer in high-current applications. Comparing a 'basic' alkaline battery from one manufacturer, with a 'high current' one from another manufacturer would not be a fair comparison.
Further, Duracell (and others) now also offer lithium batteries (at a much higher price) for those who want the maximum life from their batteries in high-current situations. There's probably very little difference between the lithium batteries offered by different manufacturers but it would be unreasonable to compare such batteries against alkaline or zinc chloride batteries.
Chris