If establishing great market share were the main objective, I would agree - standardize and be done with it. The somewhat chaotic mode of free and open source to try numerous different models has the effect of exploring many alternatives at a very moderate cost.

From a standpoint of only commercial offerings, sure, having no more than a few choices (three to five), similar to most of the major industries, tends to work well. Even there, though, if you look at it, there are a few dominant players, but lots of fringe smaller players.

I do not agree that cutting out all of the options and focusing only on one is the way to go. I do believe, however, that within the commercial community that standards and consensus are good things, particularly as size and scale emerge. But in that space, it is industry itself that ought to drive such things. Hobbyists and developers in the free space ought to do whatever works for them. If they get synergy with others, great, but if not, at least they get what meets their own needs - the beauty of software freedom - not found in proprietary solutions at all.