The idea Tycho would do something with his 'powers' as soon as his pool reaches 50% is just simply stupid.
Currently (in the current market) the guy makes 1000 - 1300$ PER DAY , that is 30k to 39k PER MONTH. In untaxed money even.
He would be stupid to do anything to destabilize the bitcoin market.
So what? There are lots of entities that would like to endanger Bitcoin and they would certainly bribe/infiltrate with money that would let your figures look like peanuts. But yeah, let’s just wait until this happens and trust in Bitcoin vanishes in an instant. As long as you can get USD for your Bitcoins everything’s fine.