There are some things being missed here.
First, the "appraised" value that was quoted was quite old, a current appraisal would certainly be much higher.
Second, these appraisals for government takings are invariably low. Impartial appraisals come in higher.
Third, appraised value is not market value. Last I checked, the market value of my house was almost twice the appraised value.
Fourth, part of the value of your property, is that it is "your property". At no time in the last 15 years have I been willing to sell my house for its current market value, that's why I still own it.
Fifth, Ms. Kelo had to fight for several years, just to get a more reasonable payment.
There are other points, but these should be enough to illustrate that she got no financial windfall.
There are really two big problems here.
First, is that the property was taken for "public purpose" (increased tax revenue), rather than "public use" (road, school, flood control, etc.) as required by the Constitution.
The worse problem has always been the case with "takings". The Constitution requires "just compensation", but doesn't define it. In practice this has always been a lowball amount defined by the government doing the taking.
"Just compensation" should start with a fair appraisal made by a disinterested third party, that takes into account current market value, and any doubts should be resolved in favor of the person who's property is being taken. However, the person should also be compensated for the value of having control of their property taken from them. This amount should probably be at least equal to the first value.
If "just compensation" were defined to make it truely "just", these conflicts would virtually disappear. Of course, it would cost a lot more for governments to take people's property, after making these changes, but if this ever happens to you, you will appreciate the fairness in this.
you're also skipping the part where they're just buying the LAND. she's keeping her house.