I imagine there probably will be at least an expensive one, because there are probably some people out there willing to pay more for an ad-free service than the ads and normal fee would add up to, but not willing to use the service with ads. Might not be many people, but I doubt having one more plan costs the company enough that it wouldn't make them slightly more money to have one
Cable TV ads are sent out to everyone the same aren't they? I imagine creating special tiers of ads for that would be more difficult than it is for streaming