In 2014, Congress passed legislation – Medicare Access and CHIP Reauthorization Act of 2015 – that included a prohibition against “first-dollar” Medigap coverage (i.e. Plan F). This took effect in 2020. The idea was to reduce over spending by beneficiaries who had little reason to care about out-of-pocket costs.
In 2022 Medicare for All proposals include elimination of all deductibles, co-payments and co-insurance, effectively eliminating all out-of-pocket costs at the point of service.