I disagree that sweat equity is typically assigned in new ventures, particularly in the private equity industry. I think most would view sweat equity as a type of compensation just like any other investment return. I think the only difference is the form, not the substance.
Let's say you and I start a business. We form a limited liability company in which you have 60% ownership and I have 40% ownership. You contributed all of the capital to the company and I contributed no monetary capital. But I have the expertise and run the business on a day to day basis, despite contributing no capital. After a year, we generate $1 million of profit and you get yours ($600k) and I get mine ($400k) accordingly.
In another scenario, you can start an LLC in which you own 100% of the member interest and contribute 100% of the capital. And instead of a co-owner, I am the "employee". But as an employee, you and I agree to a contract in which I receive 40% of the profits. After a year, we generate $1 million of profit and you get yours ($600k) and I get mine ($400k) accordingly.
In the scenarios, the difference between me being an owner and an employee is in form only. The substance is the same. In both scenarios I am contributing significantly to the business. In fact, we both agreed that my contribution (i.e., investment) was worth 40% of the business.