I can say from personal experience this is not true! You can help fix other people's mistakes! I was an energy engineer for a while.
You'd be amazed just how much low-lying fruit there is in terms of energy waste. I was also GOOD at this job. Instead of doing the brainless measures, I would really dig and do a lot of modeling and data mining and stuff to figure out truly optimal solutions. My fee + cost of measures were easily covered within 1-year of savings, and yet it was an incredibly difficult sell to get people to want to spend the money.
But... I had one client, for whom I had to sign an NDA, that single-handedly blew all the others out of the water. They had been emitting LARGE (like, think ~1 ton/month) quantities of sulfur hexafluoride for years. Sulfur hexafluoride, if you don't know is 23,500 times more potent than CO2 as a greenhouse gas. This had been going on for YEARS.
Our three-man team came in and was able to find all the leaks with some really nice thermal cameras so they could replace the failed seals and parts.