No, I'm not describing the Innovator's Dilemma. That's essentially the problem of getting stuck in a local maxima and the need to take a temporary loss to find a bigger hill, so to speak. I was instead trying to describe the troubles of maintaining an old system. They're intricate and all fixes must be hot-patched. Now, if you could just reboot...
For example, suppose you're at a large enterprise that has a silly expense policy involving taping physical receipts to a standard size paper, one receipt per page, then mailing the packet to India, where the pages get scanned and sent to the accounting department, which meticulously compares the receipts against the Excel spreadsheet you filled out and submitted via VBA macros (yes, this is a true story). How easy would that be to change? Compare that experience with working at a 20-person company and asking the accountant if she doesn't mind using Expensify.
Saying that a big company is hard to change isn't necessarily an accusation that the CEO is myopic.
As for what McClure meant by saying public companies will be disrupted... I'm not really sure, since he also contradicted himself saying that they'll purchase their potential disruptors. Perhaps he meant that large enterprises which do not acquire new companies will be out-competed by those who do. That's somewhat of an interesting assertion, but I don't know of any large enterprise that has only an M&A team or an R&D team. They all have both.