I guess the argument would be that big companies already have people with extensive domain knowledge who are deep in the maze, and can afford to be stealthy because they already have 1. History, 3. Theories, and 4. Direct Experience.
The other part is big companies are likely pursuing sustaining or incremental improvements that are perhaps perceived as key to beating out well known incumbents. Startups are likely (read hopefully) pursuing disruptive improvements and might expect incumbents to make classic Innovator's Dilemma errors in assessing risk.
I heard CDixon on PandoMonthly say his key founder questions would surround 'what's your secret?' I think his post provides more context to that line of questioning.
