Worked for franchisors for 10 years. You’re partly correct. What franchisees are buying is essentially a (theoretically) working business model. And in some cases the advantages of mass marketing outside the realm of possibility for an individual restaurant, etc.
But I can guarantee you that being successful requires considerable work and attention to detail by the franchisee.
They are also buying the use of the franchisor's brand. And it's therefore in the franchisor's interest to keep tabs on the franchisees and make sure they don't screw up and tarnish the brand. But in no way does that make the franchisor the employer of the franchisee's employees! Sheesh!