The problem is not that government schools cannot succeed, for in nearly all developing countries some of the very best schools are government schools. The problem is, as the LEAPS study authors emphasize, "when government schools fail, they fail completely"...
From The Rebirth of Education: From 19th-Century Schooling to 21st-Century Learning by Lant Pritchett, quoted by Brian Caplan in this post on his blog at the Library of Economics and Liberty.