Tesco effect
n.— «What is being increasingly referred to as the “Tesco effect” is pouring petrol on the high-street flames. The continued success of Britain’s largest supermarket chain is taking a bite out of the market share of many high street household names and causing some an identity crisis.» —“Bloodbath in the High Street” by Rupert Steiner The Business (London, England) Oct. 9, 2005. (source: Double-Tongued Dictionary)