It will be there when you go don’t worry. It’s been there for a few years now.
However consider there may be data plans even more advantageous than these plans for visitors (both TIM and Vodafone, the two largest providers, charge 30€ for those.
Check Vodafone for example (I’m sure TIM has something similar)
http://www.vodafone.it/portal/Privati/Tariffe-e-Prodotti/Tariffe/tariffe-per-smartphone-vodafone?icmp=T_Abb
If you don’t make International calls and use data only (and call only locally) the cost of Vodafone smart is only 10€
If you want to make lots of international calls, Vodafone Red offers you 10Gb of data, unlimited domestic outgoing minutes and SMS texts, and even 1000 international outgoing minutes (incoming calls and texts are always free to the receiver in Europe), all for 25€ plus the cost of the SIM card (which should be 10€). So for 35€ you get much more data and minutes.
Inquire at the store. Offers change all the time.