However, one new language will emerge. It will be a set of 500 to 1000 words that anyone can learn and use to communicate world wide.
Similarly to a programming language, this one will be limited in words and easy to pick up. This language will act as a framework, giving the essential people would need to have basic communication. 500 to 1000 words.
Basic English is 850 words
Here we are in 2015 and the one hundredth annual Esperanto Congress is coming.
The reasons approximately nobody speaks Esperanto now, are the same reasons nobody will speak your universal language in 2115.
None of these alternatives: http://en.wikipedia.org/wiki/List_of_constructed_languages have spread even as far as Esperanto. Whatever Esperanto did, it did something right.
(And the way you say "learn from its failure" - it's still around and widespread on the internet and available in Apps; you can learn it from http://www.kurso.com.br/ and http://www.lernu.net and talk about it at http://www.reddit.com/r/esperanto and write in it at http://www.reddit.com/r/esperante and chat in it on IRC on Freenode, or verbally with Mumble http://retbabilejo.net/ , there are decks on Memrise for it, it's in development on Duolingo http://incubator.duolingo.com/courses/eo/en/status and there are Facebook and Skype groups, Anki flashcard decks https://ankiweb.net/shared/decks/esperanto and heaps of Youtube videos in / about it https://www.youtube.com/results?search_query=esperanto ) and yet it still isn't very popular (despite the Internet), and you still had not heard of it. That's a failure of it.
I think it's more likely that most people don't want to invest thousands of hours of effort into learning another language, and those who do, do so because they like a particular country/language/culture, than any big mistake it made.