Why did Jesus curse the fig tree?

You have a good thought about this and I think you have it. There is more background to help you get a complete picture of this. Fig trees are supposed to have figs when the leaves are out. This tree had leaves, but no fruit. By the account in the Bible, this tree had leaves in the wrong time of year, also. This was a diseased tree. Jesus' "cursing of the fig tree" was more of a hastening of it's death. This may help solidify some of the things you already mentioned.