The gist is,
the tried and tested 5000 km (or slightly more, for synthetics) is a fine and okay rule. Cars running on standard mineral oil have gone easily till 300k and above and still perform fine. It is proven
If any super expensive oil even does last long enough , the carbon content that would have been drained away at 5k will be stuck for twice ( or even thrice more).
if the oil turns out to be fake, it is staying 3 times longer in the engine, to do much more damage.
at best, even running such an oil for a longer interval, you are only matching the expense of two oil changes in the same number of kilometers (but raising the risk)
If there is no benefit, Why take the risk?
Moreover, some of these oils are Api certified, others are not.
Using Non Api certified oil will damage emissions equipment.
For normal road cars, there is no significant benefit, worth going to special places to find oil and then risking long oil change intervals.
