Practical, but we already got one, that is English. Even this post itself is written in English to reach bigger audience.

And I would argue Esperanto is hardly universal for the world, more for european languages.

This is particularly noticeable in Europe. Due to the European Union's thinning/erasure of borders, there is an order of magnitude more inter-European travel and mobility than 10 years ago. And the most widely understood language between these travelers is English. In Barcelona, vendors would speak to Dutch and Chinese tourists in English. Even in Paris, famous for its disdain of English, the language is fairly widely spoken, not so much to accommodate the British, but visitors from the rest of Europe and the world.

Folks quickly figured out that instead of learning multiple European languages (and even then, only be able to communicate with other Europeans and people from former European colonies), they could instead learn English and be able to communicate with not only Europeans but people from Asia, the Middle East, etc.

English is used even among people of the same ethnicity. I was with a friend at a restaurant in Chicago's Chinatown, and noticed that my Cantonese-speaking friend had a hard time conveying her order to the Mandarin-speaking mainland Chinese waiter, so they both switched to English. The communication was successful.

That is a very good idea. But in order to be successful such a language needs to be spoken by a large share of people internationally. The best language we have for this is English. It's not perfect, because in large parts of the world, particularly in Asia, many people don't speak it. But it's far better suited than Esperanto in almost every imaginable way.

The nationalistic policies around WW1 and after put a stop to it.

I think it's a tremendous shame... it would be so nice to communicate with everyone in a simple language.

Note that such a language would not actually need to be actively spoken in normal live much. It just needs to be simple enough to be learn in a short amount of time and to have international backing so it is taught in schools.

Almost by definition - if a language isn't "spoken much" - it isn't really language. But rather a collection of rules and definitions.

"If a language is (or never has been) spoken much..."

it is easier to learn, even for non-europeans.

it is nationally (edit: i used the wrong term 'politically' before) and culturally neutral.

english wasn't always the most used language for international communication. until a century ago, that was french.

english replaced french because of the success of british colonialism.

there is no reason why some day esperanto could not take its place.

it is for example conceivable that people could use esperanto as a communication language with foreigners to avoid english domination out of a conservative isolationist motivation.

i edited my post to clarify.

by comparison, the speakers of latin are all dead. so, while latin has a rich historic culture, it is not dominated by any living culture.

likewise, esperanto is not dominated by any living culture because its speakers come from all over the world.

In theory, yes - but not in practice.

Which is precisely what the above commenter was saying.

that would be like saying, phones are not practical because not everyone has one. or maybe facebook or google+ are not practical because not everyone is on them.

but that is a limitation that has nothing to do with any inherent quality of esperanto, only with it's lack of popularity which is something that can be changed without needing to change esperanto itself.

Might as well just tell the world to keep using English, or make Westerners learn Mandarin.