Past colonization happened because individuals made choices they felt would benefit them.

Even if the only goal of colonization is getting resources (which I dispute), some individuals will risk colonization to get resources that they can't obtain at home. Resources are not evenly distributed across a population and, and every piece of land is owned by someone, but not everyone owns land.

The cost of space travel will continue to drop, and at some point it will make sense for people to seek their fortune there.

Moreover, we didn't land on the moon in 1969 to get resources, and we're not going to land in the 2020s for resources. The reasons are complex, and not always logical, but they are definitely not about resources. I don't see any reason why that would change in a hundred years.