So, I agree with you to an extent. From a purely theming perspective, having any brand in the park is bad. Having “sponsored by Enterprise Rent-A-Car” under the TRON sign won’t be great, but it makes a lot of sense from a business perspective, and the thematic concession doesn’t weaken the product enough to override the business perspective. To the contrary, it would be prohibitive to paint the enterprise logo over the TRON canopy, because it actually weakens the product significantly to the point where it could affect consumer perception of the product.
This is why you’ll never see a Panda Express in the China Pavilion. It weakens the perception of the product by bringing in a cheap fast food place, and it significantly hurts the brand image to the point that it could turn off consumers.
So, in order to maintain their business, Disney is put in a unique position where theming is a business strategy, but strategic partnerships can be mutually beneficial without detracting significantly.
Starbucks is an especially unique partnership, because it is viewed in an incredibly high regard by most consumers. It is viewed as a premium product, which when paired with Disney theming that dominates the spaces with a few direct Starbucks callouts, makes a unique space that is mutually beneficial to consumers, Disney, and Starbucks.
And while Main Street Bakery would not have been empty, every single Disney Starbucks location outperforms its previous tenant by a pretty large margin.