What was unconventional is now conventional the key is money and at what point do you make it. We go back to Monty Hall and The Price is Right!
I would not go that far to say shales are now ‘conventional’. It is not the definition of conventional resources, which remain the overwhelming type which the world produces.
The unconventionals are still in their infancy, so I would not in any way make a claim they are now ‘conventional’. Much is still being worked to make them more mainstream.
As an example, the Permian has just recently began drilling more horizontal wells than vertical wells.
For the rest of the world, vertical remains the choice. There is plenty of conventional oil to extract and it is far cheaper than the unconventionals.