The Queensland state govt went down this path more than a decade ago.
The policies and legislation was derailed (wound back) with the election of the LNP Newman Govt, 2012-2015.
With 37% of the two party preferred vote the Qld electoral system smashed the ALP to hold only 7 seats out of a total of 89 seats in the Qld Parliament. There is no upper house. The current ALP government is gun shy of reverting to the previous policy in full.
It demonstrates why enforced change as discussed by @syncretic
is such a difficult path politically.
Product promotion (food products as @BrendanMays recently suggested) supported by reliable green labelling is a soft persuasive approach to the consumer.
Any system of green labelling will most likely need mandatory requirements and regulation to be reliable? This requires political initiative. If it is a significant vote catcher the counter argument is it is not required as those who care will already have made decisions on which products to avoid. So no need to legislate meaningfully.
Mandating at a higher level for greener food (lower environmental impact food production) or making less friendly food products more expensive may be even more difficult, likely effective, but high risk politically.
The outcome - political indecision is easy to defend, if it evades the difficult. Look to how the policy proposal to implement improved emissions standards on motor vehicles has been twisted to ‘my Ute or 4WD is going to be taken off me and I’ve been grounded’!
Fact vs Ignorance?
Community vs self interest?
Fortunately for vehicle emissions most of us are fully aware of the concerns and also the relative impacts of our decisions on which vehicle to use or purchase.
For food products, the environmental impacts are less evident.
Several are topical. Soil erosion, fertiliser in run off, agricultural spray drift, carbon loss in production and transport.
Soil biological degradation, chemical residue accumulation, processing carbon footprint, waste disposal, packaging etc are also important considerations.
Is how all of these factors are included in a reliable rating system, as critical to success as having support for any such system?
The current iteration for RW tanks and HW systems.