Of course it's done piecemeal. That's the beauty of a partworks model. You get certain parts each month, and then you get to build it and wait with anticipation for the following month's shipment.
Plus it's a good way for them to get more people into this. How many people do you know have a little over $2000 to spend on a model of the Titanic all at once? This way, people who don't have that kind of money up front can still take part in this great kit.
Still, if you're not a fan of partworks kits and you want the full model up front, you might check out the Trumpeter 1:200 Titanic. But, be forewarned, it's going to require a LOT more work than this one is. The biggest thing: you'll have the paint all the parts, including the gigantic hull section on your own. At least with this, a lot of the work will be done for you. Plus the Trumpeter one is all plastic, not metal like this bad boy is.