The F-117 was flying a decade before we ever saw it. There are things in development we won’t see for another decade.
The F-117 is being retired because it is old, expensive to maintain, and inferior to the JSF. It never had any air-air capability, which was a drawback.
Most programs are generally in the open, with certain aspects kept secret. e.g. the B-2 and F-22. Only a very few become operational without general knowledge, e.g. the U-2 and the F-117.
But its fun to speculate. Perhaps we captured a Klingon cloaking device ;-)
People would never believe how far that airplane was flown under the cover of darkness.