How would you raise capital for operations separately from LPs? What's the upside of that for any investor? Do they get part of fund returns? Nobody is giving any kind of fund any money unless they get part of the fund returns for it.
So they take 40% of future portfolio returns, and then sell half of that up front in return for investment of 2% of total funds managed and end up exactly where we are now but with added complexity....
Efficient markets.