Why, in a business sense, would they stop? If there is a market for larger screens then it's in their business interest to provide the market with what it desires.
If they reach a size point in their devices where the market refuses to buy, it's at that point when they will stop making them larger. But until then, and it doesn't appear that 5.5 is the threshold, they will keep making them bigger and bigger.
I have the Note 5.3 & 10.1. When this one hits US soil I will also have the 5.5. Personally, I say keep going!