My sense is that Dr. de Geus is fending off pressure to acquire, as would any other leader of the Big 3. They would rather speculate in private (and don't forget about legal liabilities for C-levels!). But the Big 3 have been acquiring, albeit slowly, and the assets tend to be more mature than in the past.
All of the Big 3 originated as start-ups, Aart de Geus himself can trace back to one that became Synopsys. Both Cadence and Synopsys ancestor companies had Alberto Sangiovanni-Vincentelli on their boards, they didn't compete against each other (but when they grew and they did, the professor chose Cadence). Mentor Graphics was a spin-out from Tektronix with five people (three founders). Amongst them, the Big 3 can trace back to maybe two dozen people!
What I would like to see is excitement returning to EDA, of the kind that the greater startup world is experiencing and can be seen in events like Startup Festival (Montreal), TechWeek (Chicago) and many that take place in the Bay Area, London, even Berlin ...