You give them credit for Postscript and for pdf. Pdf is essentially Postscript, zipped, with some of the code commented out. So really they deserve credit just for Postscript.
Except that postscript was largely created at Xerox PARC, before John Warnock and Chuck Geschke left. Warnock and Geschke wanted Xerox to sell Postscript (then called Interpress) as a standalone product, but Xerox chose not to. So the two left and created Adobe to sell Xerox's idea.
So anyway their one great thing, Postscript, wasn't created by Adobe.