The worst part of the EROEI is that "once upon a time" we'd get upwards of a hundred barrels of oil by way of "investing" the energy that we got out of single barrel. Today, that number has gone down substantially. Some fields will ultimately get as bad as three-to-one or so. This means that to keep producing from such fields, you have to drill more and more holes, install more and more equipment, etc. until it's just no longer cost-effective to bother.
And then there are heavier oils--oils that have a lower API gravity require far more processing and different processing equipment in a refinery to make the products that you want. A lot of what Saudi has left is heavier oils that nobody really wants because they don't want to have to retool to that extent. BigOil's going to have to take all those evil profits and reinvest them in order just to try and maintain an even production keel as it is.
Right, but whether it's cost-effective is not important or relevant to the consumer. Why? Because as long as the product is available, the cost effectiveness of drilling in one spot or another is not our concern. The oil companies are the once you must invest, and therefore risk that investment on drilling is any specific spot, since we merely have to determine if we're willing to pay the price at the pump.
Same is true for the oil specific type of oil available. Naturally, if the amount of light-sweet crude declines, the resulting higher price for oil will make more difficult to produce, and heavier types of oils, more cost effective, and thus making them wanted.
Even if we were to assume what you said is true, what difference does that make when production is still increasing? Even if the EROEI is reducing, prices are still very low when you factor in inflation, taxes, government requirements, and mandated expensive additives. We have the cheapest gasoline in the world barring countries which subsidize the cost.
To put it bluntly, it makes no difference is the EROEI is 1 to 1, as long as oil is under $50 a barrel, and gasoline is under $1.50 a gal.