Apple, Microsoft and Intel have dominated the personal computer industry for almost all of its existence, and their relative positions within that market have been remarkably stable. Therefore as every year passes with that still true, the expected future lifetime of that triopoly increases.
There are many counterexamples in business - Nokia, Blackberry, Sears (the names live on, but as shells of their former selves.) One has to be wary of survivorship bias when looking for the Lindy effect.
