Facebook employs many software engineers but isn't inventing much in software
React, Jest, and GraphQL (among many other projects that I'm less familiar with) were created by Facebook, many of which heavily altered the way that people do programming in the relevant domains. Without knowing what exactly you mean by "inventing" in software, I think you'd have a hard time arguing that they're done none.
Many of the large tech companies have similar contributions, depending on what sort of work they're doing. It's not even just large tech companies - a number of much smaller companies I've worked for have some level of open source contributions, which often are representative of "invention", and arguably a lot of the actual products that companies create could be described as "invention" as well.
Without a further explanation what you'd consider an "invention" vs not, it's hard to say whether or not there's any "there" there with your original point.