It's not necessarily a recent phenomenon. These (wiiiide) cars (with wiiiide rear tires) from 1991 overtook one another less frequently than this year's cars.dans79 wrote:Over the last several years, teams have have adopted methodologies that are increasingly more sensitive to the wake of the car in-front of them.
If we go by Mercedes' claim that 45.1% of overtaking in 2011 was due to DRS, it was apparently more difficult for cars to pass one another in 1991 - 30.94 overtakes per GP - than it was for cars from 2011 to do so without DRS - roughly 33 per GP (with the caveat that 2011 featured Pirellotteri tires, but I don't know how to parse Pirellotteri overtakes).
Ultimately, overtaking is concerned with neither downforce nor mechanical grip individually; it's about total performance differentiation. The kind of performance differentiation required for semi-routine (?) overtaking on circuits that have but a single racing line - 1s to 1.5s - is also the kind of performance differentiation that results in processions, because cars capable of such overtaking inevitably begin races well ahead of the cars they can overtake. The mechanics of turbulence and tire degradation are both subservient to this reality, and trying to overcome it is the Sisyphean job I referenced earlier.