Well, yes, if Rome never expands past Italia and doesn't get in any major wars where they capture a fuckton of slaves that made the development of latifundia possible.
The best way to do this? Have the Roman religion develop in such a manner similar to the Aztecs in that human sacrifice of war captives happens rather than enslavement.
However, the wars themselves helped in this matter due to the fact that it was the small landholders who were the ones fighting due to the property requirements, and the ones dying and leaving their families impoverished and willing to sell their land. So get rid of the property requirements earlier on and make war using the proles and the landless in the legions rather than just the small landholders and property holders.
So you either need for Rome to never really rise (perhaps the sack of Rome by Brennus leads to a return of the Etruscans), a strange evolution in the Roman religion, or you need for the Roman military to scrap its property requirement much earlier.