If they didn't destroy Bitcoin is not because they never wanted to, but because they can't.
They can't?
1: Spend the necessary capital to 51% attack the network. Destroy it.
Good luck creating another bitcoin that people will trust after that.
2: Wire $20M-$50M on various bitcoin exchanges and short it down to single digits and beyond in one go totally destroying confidence.
Currently there are around $15M in bids (lol) on all major exchanges combined and plenty of longs that can be completely margin called ($23M+ on bitfinex alone for example), it should be fairly easy.
Not only $20M-$50M is nothing for them if they are inclined in "killing" BTC, they would also make a very good profit on top of it.
They
could destroy bitcoin is they wanted to. Thing is, they probably DGAF.