Interestingly, some classic monopolies, like the old AT&T and Xerox, innovated tremendously but would fail to capitalize on those innovations (Bell Labs & Unix, Xerox and the Mouse/Menu/etc GUI).
I think this is the more common failure mode - a lot of innovative work happens at big companies, but those innovations never make it to market because commercializing a product requires a large investment in, well, finding customers, and the innovators at big companies are not empowered to do this.
There is still a ton of innovative research work coming out of Microsoft, Intel, and even IBM, but typically instead of being commercialized and profited from, it languishes until the company shuts down the research lab and the scientists involved get jobs elsewhere.
The original AT&T was an official government monopoly so the very existence of Bell Labs was in part a tax it payed to avoid problems. As I recall it also wasn't allowed to do things like sell UNIX(TM) for serious money prior to the United States v. AT&T 1982 consent decree ... which I notice is the same year UNIX System III was released.
That isn't even an example of disruptive innovations almost never happening in established companies, Xerox just wasn't doing that sort of thing to begin with. Well, they bought Scientific Data Systems at the top in 1969 and fumbled that by the middle of the '70s....
