Are you implying that Sun had a larger impact than Microsoft? Of course "larger" is not well-defined if the dimension isn't specified, but in the financial context it is used, I would say that is a fair assessment.
Most servers were migrated from Sun to Linux (with minor hiccups). Sun basically set the standard for security and reliability that led to the successor instead of OS/2 or MacOS or ReactOS or whatever. Microsoft HAD to change their OS to meet the needs of the users (ANY security, more interoperability between ()nix and windows, etc).
The statement is either poorly phrased or wholly inaccurate, depending on your point of view.
Between 1988 and 1998 Sun stock increased 10x and Microsoft stock had increased 100x. By converting 15% of his Sun holdings into Microsoft stock he outperformed his Sun holdings.