Question: After which world event, did retail establishments in the U.S. began to pursue a high-volume, low-profit-margin strategy in a type of store that sells products at prices that are lower than the typical market value and for example sells Scotsmac, an alcoholic drink consisting of a blend of wine and whisky flavouring, in 700ml bottles?

Context paragraphs:
Royal Stag: Royal Stag, also known as Seagram's Royal Stag, is a brand of whisky launched in 1995.  It is available in many countries across the world in various pack sizes and has emerged as a global brand of whisky from the house of Seagram’s.  It is Pernod Ricard's best selling brand by volume.  It is a blend of finest grain spirits and imported Scotch malts.  It is commonly available in 1 L, 750 ml, 375 ml and 180 ml bottles and also available in 90 ml and 60 ml bottles.  The brand is named after a species of deer famous for its antlers, that is also featured in its logo.  It is produced in several company-owned as well as bottler-owned distilleries.  It was the first whisky brand launched in India that did not use any artificial flavours.

Imperial Blue (whisky): Imperial Blue, abbreviated to IB and also known as Seagram's Imperial Blue, is a brand of Indian whisky, owned by Pernod Ricard, and launched in 1997.  It is a blend of Indian grain spirits with imported Scotch malts.  It is commonly available in 750ml, 375ml and 180ml bottles, and also available in 90ml bottles.

Scotsmac: Scotsmac is an alcoholic drink consisting of a blend of wine and whisky flavouring.  It is sold in 700ml bottles from discount supermarket stores such as Netto and Lidl across the United Kingdom.  Scotsmac has a strength of 15%.  Also known as the "Bam's Dram" or "Wham's Dram", it was once blended by D & L Ariano, imported and bottled by J.H. Wham & Son (Largs) Ltd.  It is now bottled for Accolade Wines in Guildford, Surrey.

Beenleigh Rum: Beenleigh Rum is one of Australia's oldest brands of rum.  It is produced at the heritage-listed Beenleigh Rum Distillery at Eagleby (formerly part of Beenleigh) in the City of Logan, Queensland.  This Australian Rum is 100% Australian made from all local ingredients and is available in 700 ml Dark Rum aged for 5 years, 700 ml White Rum and Australia's only 700 ml Honey Liqueur Dark rum rum grades.  All three offers are fermented from Queensland molasses.

Discount store: A discount store is a retail store which sells products at prices that are lower than the typical market value.  A "full-line discount store" or "mass merchandiser" may offer a wide assortment of goods with a focus on price rather than service, display, or wide choice - such as Aldi and Lidl; a "speciality", "single line", or "category killer" discount store may specialize in specific merchandise such as jewelry, electronic equipment, or electrical appliances, relying on bulk purchase and efficient distribution to keep down cost - such as Toys "R" Us and Staples.  Discount stores are not variety stores, which sell goods at a single price-point or multiples thereof (£1, $2, etc.).  Discount stores differ from variety stores in that they sell many name-brand products, and because of the wide price range of the items offered.  Following World War II, a number of retail establishments in the U.S. began to pursue a high-volume, low-profit-margin strategy designed to attract price-conscious consumers.  This strategy has received renewed interest from retailers and customers alike stemming from the Great Recession that began in 2007 that forced buyers to revisit the approach to the products they wanted.

Johnnie Walker: Johnnie Walker is a brand of Scotch whisky owned by Diageo that originates from the Scottish town of Kilmarnock, a large burgh in East Ayrshire, which is where the brand's creator, John Walker began making and distilling the whisky in the Johnnie Walker Bond located in the town centre.  It is the most widely distributed brand of blended Scotch whisky in the world, sold in almost every country, with annual sales of the equivalent of over 223.7 million 700 ml bottles in 2016 (156.6 million litres).

After Dark (whisky): After Dark is a brand of Indian whisky, manufactured by Radico Khaitan.  The whisky was test marketed in 2010, and rolled out nationwide in India by September 2011.  It is a 100% grain-based whisky manufactured at Radico's Rampur distillery.  It is available in 750ml, 375ml and 180ml bottles.  The brand's tagline is "One Life, Many Passions...Why wait".

Wee Beastie: Wee Beastie was a brand of alcopop, as it is commonly referred to.  It is part of the RTD (ready to drink) market and is popular in Scotland.  It was available in 275ml and 700ml bottles and was 5.4% ABV.  The 700ml bottles are labelled "Big Beastie".  Wee Beastie is owned and distributed by Inver House Distillers.  The drink is described as a carbonated, premixed blend of vodka, taurine and caffeine, flavoured raspberry and blackcurrant.  The taste is similar to Red Bull.

Melbourne Bitter: Melbourne Bitter is a beer brewed by Carlton & United Breweries, (or CUB) a subsidiary of SABMiller.  While originally having an ABV of 4.9%, it has since been reduced to 4.6% ABV.  Melbourne bitter is available in 375 mL bottles "stubbies", 375 mL cans "tinnies" and 750 mL bottles "longnecks/longies".

Rev (drink): Rev is a 7% ABV vodka-based cola beverage (alcopop), infused with guarana.  Rev is manufactured by FBM Distilleries in Brampton, Ontario, Canada and distributed exclusively within the country under license from Bacardi.  It is currently available in blue as Rev Energy and Rev Low.  Purple, red, and green have been discontinued.  The drink is sold in packs of four 330 mL bottles and single 473 mL bottles.

Supporting paragraphs: Scotsmac Discount store
Answer: World War II