Specifically I've heard that about the Energy Returned On Energy Invested (EROEI) which is the oil and gas industry's equivalent to Levellized Cost Of Electricity (LCOE)

for reference the spindle top formation in Texas (that started the oil boom and kicked industrialization into high gear) was an EROEI of 100:1. You burn a barrel of energy, get 100 barrels.

Nowadays things are far more bleak... Our average EROEI is around 12-14 as a global average. Tar sands is 2-4. Shale oil (fracking) isn't much better at around 4-6, sometimes less.

As an aside on why fracking is so low: you put a loooot of energy into drilling and banging, and then you lose 70% of your flow after a year. 2 years after drilling the well is dead and you need to do it all over again.

A lot of economists (and other experts) have placed a point of no return for the world economy around an EROEI of 7, which we should reach in roughly 10-15 years.

Once energy returns get that low the oil industry exists to support the oil industry. There isn't enough surplus energy to run a complex globalized nation. It's a bit like starvation when all we've known is a surplus of calories for 200 years.

This. And we are using remaining supplies of fertilizers as well (fossil sources of minerals) too, and pooping them into the rivers and oceans. So many one-way processes in our way of living.