Yes and no. You are saving the hospital on their readmission penalties, but those currently only apply for three conditions (CHF is one of them). Furthermore, the penalties are not always enough to cover the increased revenue that the hospital gets from the readmission - in other words, some hospitals may actually make a profit from the readmission even when the penalty is factored in.
Also, the "up to 2%" is itself complicated. Because of the way the penalty is deducted, other seemingly-unrelated factors (like the patient and insurance demographics of the hospital) have a huge impact on how large the penalty is, even holding everything else constant.
> Hospitals can and should be charged for this
Currently, even the hospitals that receive the highest readmission penalties are not willing or able to pay (much) money for reducing readmissions. The way their budgets are structured doesn't really allow for this[0].
I say this from experience - my startup also creates a product that happens to reduce readmissions (though this is not our primary goal), and one of the reasons that we emphasize our other (larger) benefits for the hospitals is that most hospitals just won't pay much for a product that reduces readmissions.
On top of that, it's also a very crowded space. Health Recovery Solutions is a for-profit company that does more or less the same thing: http://www.healthrecoverysolutions.com/
[0] Yes, it's inefficient, but that's a separate discussion.