Your are correct. The economy is slowing down, natural gas is once again the preferred boiler fuel and OPEC is cheating on quotas. What a short term oversupply doesn't translate to is an indication of anything long term.
To give some idea, the last estimate I heard of the impact of the collapse of oil prices to around 10 dollars was the permanent loss of about 1 million barells per day from marginal production in the US that could have continued for years, but was totally uneconomic at lower prices. When this type of production gets plugged and abandonned, it is a very good bet that it will never be brought back into production.
Low prices lead to lower production which leads to high prices. The key point however is that either way the low cost producers like Saudi Arabia and the Gulf States increase market share.
BTW, the difference between optimal supplies of crude and products; and current supplies is a lot of oil, but is really only a few days worth of consumption.
I think I read on OILNEWS.COM that they cheat about 1.7 million barrels per day. That is 19 dollar oil. Imagine how much they would cheat for 30 dollar oil. They don't have the discipline to hold the coalition together and maintain high prices. When prices go up demand goes down pretty quickly and before long all the oil storage tanks get filled up and there is a glut, kind of like we have right now.