Increasing the wall thickness of a pressure vessel has rapidly diminishing returns (especially in a brittle material like glass), increasing shipping weight for very little benefit. On the other hand, scanning for defects in reprocessing is easily automated with very low marginal costs.
The company who is able to get away with making the cheapest bottles which breaks the most, still benefits from other companies which are contributing to a recycled glass availability pool.
The incentives are such that companies are trying to make the crappiest, least recycled bottle from virgin material, since there is no guarantee they will get a bottle they manufactured, back at the plant.
