Not everyone wants to deal with the bullshit associated with ownership. Owning a business is not the same as doing the labour that makes the business money - there's a bunch of other crap like dealing with taxes, licensing, insurance, marketing, and liability. It's great that OP is willing to offer an ownership stake but not everyone wants it. In one small business I'm aware of, I know an offer like this was made and the person/employee declined because they didn't want all the additional stress of work required for the business to legally exist and function and instead wanted to stay on the tools so to speak. They found it was better for their health/mental health limitations. Now that person is well paid and has a senior role, but isn't an owner.

There is a non trivial amount of labor that goes along with owning a business that is necessary for a business to function. It is not so much labour that small business tyrants should be exploiting labour like they do, but it is work and it is almost always different in nature than the type of work that the business does that actually makes revenue. Paying someone super well and respecting their opinion for decision making purposes without an ownership stake is a respectful option for OP.