The answer is Food shortage.
The primary achievements of John Rolfe had to do with agriculture, since he was an early English settler in the colonies who was primarily responsible for making the exportation of tobacco from Virginia incredibly profitable.
Old Major is the allegorical figure for Karl Marx or Vladimir Lenin, depending on your interpretation of the text. Both men stood for basically the same thing, and these things was what Orwell was exploring in the novel.
- It had foreign spheres of influence.
- It failed to institute reforms.
- It avoided modernization.
I hope this helps :)