The answer is "the modern, complex economy is self-correcting and no longer has the capacity to deprive individuals of their rights".
Modern liberalism developed as a response against free-market capitalism, trusting this had prompted numerous people not being free. Freedom could never again essentially be characterized as 'being allowed to be alone. Though early types of liberalism saw freedom as accomplished through a constrained part for the state, modern types of liberalism adopted an altogether different strategy.