"Every single developed nation" is a very broad generalization that I'd be skeptical of being true. I'd also dispute that all countries are pro-corperation and instead state that most countries are pro-economy.

Corporations are just a vehicle for organizing work and profit around a venture. There are many other ways to organize work that have nothing to do with corporations or unions. Consider partnerships, sole proprietorships, cottage industries, co-ops, and more specific arrangements within those vehicles like profit sharing, limited partnerships, and employee ownership (not to be confused with stocks/options, though they are similar in concept).

Capitalism can take many forms, and not all of them require we turn the way we organize work and wealth generation into a zero-sum game between entrepreneurs and laborers. It's just the first thing we've found that's worked out in the environments it's been attempted in. I think there's room for businesses and economies to try out novel models for organizing work, and I suspect many of them could get us better or more efficient trade-offs between profit, productivity, and general welfare for all parties involved.