If it will make GameFreak money, then it makes sense.
I'd like to expand a little on this:
GameFreak doesn't only check if something is expected to be profitable. Gen. IV remakes probably would be, but that's not to say they'll automatically be guaranteed to be made.
You see, GameFreak has a release schedule they'd like to stick to. Years in advance, Nintendo is planning when to release games, and I'm pretty sure they're working closely with GameFreak, to plan out new console releases, or to tie games to new planned services. It all has to fit in somewhere, and I'm sure it's all quite complex, but bottom line is, we're getting a new main series Pokémon game every 12-18 months or so. The release dates, or at least the release fiscal quarters, are decided on years in advance. Concepts and themes and such comes later, and game development even later than that again.
So, whenever the next date looms, GameFreak have to decide what kind of game to make. A new generation, a remake, a sequel game or something new entirely? Each choice represents a different degree of new development, or reuse of old data. Will they have to design a new region? A new generation usually implies a whole new graphical engine, new Pokémon, the whole shebang, while a "sequel game" is mostly the previous game recycled (then again, a new generation can be regarded as a foundation for several different games, so they get a lot of return on those invested resources). And also, a different degree of expected sales. One choice might sell a lot better than the others, and if they choose wrong, they're going to lose out on a lot of income. They only get one cash cow release like this every year, at most, so they really have to make sure they pick the right game to make.
So GameFreak always makes sure to consider a few different options, and then compare the crap out of them. I'm pretty sure that "remaking D/P" might come up as an option quite soon (as they're probably well into planning Gen. VII already), but there will be other options too. And while a D/P remake might earn a bucket load of money, maybe they figure that a sequel game to the main Gen. VII games will make
two bucket loads for the same investment. If D/P remakes are being out-competed by other alternatives several times over, the "nostalgia window" will eventually close, and there'll be more fans craving a Gen. V remake instead.
So even if something would make GameFreak money, it's not guaranteed to be made. Alternatives will be considered, and the best alternative (representing the optimal mix of investments, projected sales and risk) will be chosen for the relevant release. It might be reconsidered for the next release, but it'll always have to stand up to alternatives.