Speculate as to why Microsoft and Nokia initially decided to form a partnership rather than have Microsoft

Question:

Speculate as to why Microsoft and Nokia initially decided to form a rather than have Microsoft simply acquire Nokia? Why was the unsuccessful?
Partnership
A legal form of business operation between two or more individuals who share management and profits. A Written agreement between two or more individuals who join as partners to form and carry on a for-profit business. Among other things, it states...