As technology and society change some jobs or entire industries become obsolete. A lot of manufacturing is are automated. We haven't had switch board operators in several decades. Movie rentals chains like Blockbuster Video have mostly been replaced with online streaming services. Within our lifetime we might see more shipping jobs become automated. 

The main arguments against changing to renewable energy sources or moving away from for profit privet health insurance is the loss of jobs.  This is a legitimate concern, that would be a lot of jobs lost very. What makes some industries worth saving? Is it the number of people employed, the quality of the product or jobs?

In my opinion the  government shouldn't be stepping in to save any industries but it should be mitigating the effects of change. There should be more education and training programs in industries that are growing and helping people transfer from working in the oil industry to maybe related greener industry jobs. A lot of the plastic pollution comes from manufacturing and packaging, the government could have incentives to change to plant/algae based plastics instead the technology for this has been around for several years but it is a large investment to update equipment and things like that.