They certainly did try to make San Marino a communist economy. It's just that they didn't think that this meant the immediate nationalisation of all property.

They certainly did try to make San Marino a communist economy. It's just that they didn't think that this meant the immediate nationalisation of all property. They were far from alone in doing so, notably Marx and Lenin agreed and advocated for similar trajectories, so it was far from a fringe position. A popular communist program for developped countries is to remove all political influence as a result of money, encourage cooperatives, nationalizes key industries (as in China), and manage productive surpluses to provide for everyone, removing markets where they are zero sum of negative sum (housing, etc...), and coordinating markets for optimum growth, until the economy is developped enough that the entirety of the local economy can be ran as either part of the nationalizes sector or by cooperatives. It's a fairly mild program when compared to Stalin. There is not really any reason to abolish private property until the economy is large enough that it can be fully run by the workers from a communist point of view - Stalin did it because he judged that heavy industry was not developing rapidly enough, which was a strategic judgement mostly on grounds of the preservation of the state (and therefore himself). Otherwise Lenin's policy of managed capitalism/socialism for a hundred years or so was in place.