That is not how the illinois program works (the one on coursera)
Each of the 18 courses is like this:
"One segment is self-directed, noncredit, and covers basic foundational content, imagine it to be your interactive textbook. This segment, housed on the Coursera platform, includes involvement in an open, global classroom. This segement for each course is free for knowledge sake....."
"The other segment is the advanced graduate-level for-credit segment, that corresponds to the foundational material in the noncredit segment.
This segment, based in the Illinois Compass platform, will take you deeper into the material with personal interaction with faculty in the form of live classes, personal feedback, office hours and advanced case studies. You will also do project work with teams of fellow students."
source:
https://onlinemba.illinois.edu/admissions/access-points/enroll-credit-course/ section "How it works"
As you see, the whole material for an MBA is not online in any case.
Moocs are great source of knowledge and many of them are on par with graduate or undergraduate level (mostly those at edX-micromasters or coursera-MasterTrack)
But I don't think anyone offers the whole (or even 1/4) of the MBA knowledge for free
I mean, anyone can buy the books (most MBAs clearly state what books are used in the curriculum, it is no secret) and study on his/own but the experience is really really really nowhere near the same as in a business school - or that of an online MBA designed with interactions, feedback, case studies, live hours etc