If the new CTO is so great he'll be moving up & out eventually and by then you can (re)fill his shoes better than he did the whole time. If he's not so great y

If the new CTO is so great he'll be moving up & out eventually and by then you can (re)fill his shoes better than he did the whole time. If he's not so great you'll exceed his abilities after a while and become truly more valuable, especially to this particular company where you were the original CTO. That would also be when other pastures are the greenest. It's not revenge, it could be considered a business requirement that you now focus on the technology itself until you far exceed the acceptable benchmarks set by the new leader/decision-maker, while also building from experience the ability to avoid their type of leadership & decision-making weaknesses that become apparent, without you having to carry ultimate blame for failures along the way.