There doesn't need to be one universal answer to this suggestion; it would be a boring suggestion if that were the case. Instead, you could look at the market for white-collar jobs and break it down looking for lucrative subsets, and then devise some kind of apprenticeship scheme.
If you could eliminate the 4-year degree requirement for HR directors, company controllers, purchasing managers, or jobs like that, replacing it with something tailored to the specific job, you could allow people to get an early start on a white-collar career while offering them opportunities later in their career to get something like an MBA or a JD.
But because the only current credible signaling mechanism we have is a 4-year degree, there is currently no good way to get the kind of job that might legitimately demand an MBA or a JD without first getting a degree in Russian Lit.