No, it's not abandoned -- this is just how Italy looks

This Eataly isn't just a small concession within a train station mall -- instead, it took over an entire station building! Ostiense is Rome's closest major train station to Fiumicino, and when the rail link was built in the 80s (as part of the 80s-90s regional rail building boom I mentioned in the travel blog series), Trenitalia decided to build an entire second station building at Ostiense just for the airport train services. It was also intended to be used during the 1990 World Cup, and (just like the Vigna Clara station/line I also talked about in the blog series) it ended up being only used for the World Cup, falling into disuse not long after. (As you can see from that link, it even had the distinctive yellow tubular structure that was the signature of Rome's 80s-90s railway expansion.) The "Air Terminal", as they called it, sat unused for around 20 years until Eataly moved in in 2012. 

As you would expect from a train station, the building has a lot more entrances than a grocery store would want to use, with most of them just sitting unused (since Eataly preserved the exterior architecture of the building), including the side entrance that lines up with the entrance to the station underpass. Interestingly, when Eataly moved in, the space at this end was actually being used for a new train station, for Italo, a private train operator that competes with Trenitalia on busier routes. They planned to use Ostiense as their main hub, but didn't last long before moving to Termini (similarly, Trenitalia wanted to use Tiburtina, on the other side of Termini, as their main high-speed hub, but also gave up after a few years). That being said, this building's second time as a station probably lasted longer than its first!