If we start from the assumption that the underlying basis for sponsorship is to sell more units (ultimately), this requires sponsorships, and the assets and campaigns that attach to them, to evolve over the term to better reflect the traditional consumer journey.
But given the assets that traditionally attach to each step in the consumer journey tend to decrease in value as we move down the chain - from the branding, media and ambassador assets that are usually utilised in generating awareness and consideration, to more digital and activation assets used at the preference and action stages - shouldn't the evolution of long term sponsorship result in reduction of sponsorship fees over time and shedding of high price assets (rather than increasing by CPI)?
And this does not have to be at the expense of sports and rights holders. Properly managed, overall portfolio value can increase though reallocation of high value branding assets and creation of higher yield engagement assets. Just requires a different approach, and a little planning, to yield much better results for both parties.