As said in the geography section, the Hudson and Delaware rivers run through these colonies. Because of these rivers shipping and commerce were very popular. Not quite as popular as in New England, but still very successful.
Because of these rivers the colonies also had very rich soil. With only mild winters these colonies were perfect for farming and it was a very popular job here.
They also had a West India Company, which was mainly a fur trading settlement. They had New Amsterdam built to protect these settlements, and any other fur trading settlements around. Many of the social systems here included slaves. Even though the slaves lives were harsh, they still had land ownership which they say makes it worth it. To conclude, agriculture, geography, and economy helped the Middle Colonies survive the early stages of its development. “The experience of ages has shown that a man who works on the land is purer, nobler, higher, and more moral... Agriculture should be at the basis of everything. That's my idea,” -Nikolai Gogol
I believe that the agriculture, geography, and economy helped the Middle Colonies thrive early