Such a scenario would need to be evaluated more in depth with actual numbers of what a malicious miner could earn vs what it could loose but still it would require taking of the majority hash-power. But here, you also assume that if a new incentive is created only one miner would go after it which is not how it would work from a game theory perspective. Although, it may be a fair concern that’s one that requires more analysis to either be uphold or ruled out.