Multisourcing is the concept of working with multiple suppliers who are also competitors.[1] Large-scale buyers, such as the U.S. federal government, may want to feel assured that there is more than one supplier for an item.
It has been described as the opposite of "one neck to wring".[2] The opposite is called sole-source.
Intel, a large corporation, was not "enough" for the x86, and so others such as Advanced Micro Devices and Cyrix were needed.
... one neck to wring ... a single source of technology