Question: What was the worst business decision of the last century?

1. Steve Jobs' pulling all R&D off the Lisa, sequel to the Apple IIe, and going to the Macintosh and NOT providing an upgrade from the IIe to the Mac?
   
2.  IBM buying the use copyright for DOS and leaving Bill Gates with final ownership of DOS?
   
3.  Other?
   

It is my opinion that the Apple IIe had 80% of the world's PC market before the Macintosh, but Steve Jobs pulled all R&D off the IIe system and built the neat toy "Macintosh", but did not provide an upgrade path for IIe data or software.

It is also my opinion that IBM, when they bought the right to use DOS from Bill Gates, thought that they were selling "iron" (computers), in the vernacular of the time, and did not realize the importance of software.  If IBM had bought DOS outright and denied Bill Gates the right to sell or develop it, the world today would be quite difference.

However, I am not sure which of these business decisions the worst was.
Please give me your opinion.