Take your example of the Open Web. I wouldn't be in software without the Open Web. I hand-write HTML and CSS to this day! But many people hate the web stack. They hate the ergonomics and enjoy better ecosystem for nearly every possible thing implemented in the web. I think ultimately, that's ok and it's "worth" having competing standards, because the alternative is - pardon the dramatics - authoritarian.
edits:
> #2) Check for prior art first. The problem may have been solved before...
I generally take issue with the statement "this is a solved problem". It ends up killing critical thought on the vine. I think everyone is better served thinking critically, and yes maybe something off the shelf is the right choice. But think critically, and freely, first.
> #3) "be opened-minded to other approaches"
contradicts the idea of building one-thing all-together no?