We don't have a link to the article so we don't know exactly what they're doing, but I feel it's unlikely that they've just replaced pints with half pints. Or maybe they have, that would be even weirder!
Oh interesting! The only time I've seen 2/3 pints sold instead of pints it seemed to just be shrinkflation as they were still extortionately priced, I wonder if consumption is down just because you're getting less for your money.
There's a craft beer place near me (The Hopbox, Ware) that sells in 1/3rds or multiples therof. Some of their 'beers' are 13%. Not sure you'd want a couple of pints of that. But, it does give the opportunity to try out different styles when you visit, and there are quite a few ladies drinking them who'd maybe not be too comfortable with a pint.
Yeah I've been to beer festivals and fancy pubs that do some lovely ludicrously strong beers that they can only sell you in halves or thirds, my grumble was regarding places that only sell cool-brand-name lager in two-thirds for the price of a pint.
What I can glean from the headline and the above comment is that the quantity being sold is only a pint in name, not in quantity, so the problem isn't per se that they might be selling ⅔-pints, but that they might be selling what they call pints but are actually ⅔-pints.