Question

What were the reasons why italy did not exist as a country?

Answer 1

Until late 1700, Italians did not see each other as part of the same country. Infact, hardly a man from Sicily could understand or speak with a man from Veneto. 
At the start of 1800, however, Europe was facing new independentist movements. This started with the France revolution, but it continued for all the 1800. 
Many cultural and political italian personalities started to think that Italy should be unite under the same country, even if their monarchs didn't want to unify at all. That's why at some point many poets and writers started to agree on what was the Italian language, and wrote some novels to unify the Italian thought. "I Promessi Sposi" from Manzoni is one example of an attempt to tranfer patriottic feelings to italians. 
However, after many wars and a lot of history Italy become one (poor) Country: the first reunion of the parliament was held inf french (it was the only language that was understood by everybody!).
That's why another father of our country said: "Fatta l'Italia, dobbiamo fare gli Italiani" (Now that we have unified Italy, We have to make people realize that they are Italians.) It took about other 50 years, with Mussolini, to complete this unifying process.

Answer 2

it was separate and small kingdoms, Austria did not want a powerful neighbor, the pope did not want to loose power over Papal states which divided north and south.

Hope this helped!