New Delhi, June 15 -- Hollywood has lately developed an obsession with business dynasties-particularly those on the cusp of implosion. It is not just "Succession", a hit series about a media baron and his squabbling heirs seemingly inspired by the Murdochs. "La Maison" transposes the same drama onto the glossier world of French fashion; a reboot of the 1980s series "Dynasty" brings it to the energy business.

Television executives have put their finger on something the corporate world often forgets: family firms are not a sideshow, but arguably capitalism's main act. They account for around two-thirds of all businesses worldwide and, according to McKinsey, a consultancy, generate a similar share of GDP. Most are small-but not all. Some of...