They had olives, bread, cheese, mushrooms, and sausage, though. Imagine being stuck in a dystopian Italy where they were one ingredient away from being able to make pizza.
The Romans probably had some kind of fried pasta called lagana (probably cognate of lasagna), the other things you mention are not quite staples, for example avocados are still pretty hard to come by in Italy.
Yeah avocados are a stretch. I included them because last time I was in Italy there was a tray of avocados with balsamic vinegar, tomatoes, basil and mozzarella everyday and at every meal at catering and I was there for a few weeks. It was delicious but threw me off. Pineapples on the other hand I've been able to find at nearly every street pizza vendor and and pineapple juice in almost every grocery and convenient store. There's no doubt Italians and Greeks were making something with their grain, wheat was domesticated not far from Italy in Turkey of course, but they weren't making pasta until Marco Polo or somebody brought the practice back from China. I think the real issue is when does "Italy" really begin, and what constitutes "Italian food"? Of course none of this really matters it's just fun to argue about mainly because Italians are just so proud of their food. I guess all cultures are and rightfully so.
Why can't pasta have been invented independently in Italy and in China (and possibly somewhere else?). After all flatbread and pizza are very very common in cultures that had not communicated.
As a matter of fact the first written mention of pasta in Italy predates Marco Polo's birth by exactly one century (1154-1254).
