I don't think that's how it works; "best" is sooo hard to define. Humans are very diverse, and have different needs/preferences. Also what is best today may not be best tomorrow (not because of the system itself, but because of changes in the environment), so it pays off to have "sub-par" systems evolve in parallel with different slightly different goals or implementations.

I don't see "open-source" as being antithetical to competition, at all. In fact, e.g. Databricks only exists because of Spark. There is competition in the open-source world too, and IMO that's a good thing.