[jmpe]

Complex question, but there are a few aspects that work against them:

- coral typically takes several years before reaching sexual maturity. Adaptability to a changing environment strongly depends on this.

- corals typically occupy ecological niches.

- acidification directly interferes with a key part of their metabolism and habit. It's like asking whether mammals can't evolve to a life without skeletons.

Corals are an extremely diverse group of organisms that interact with other organisms through complex relationships. Take them away (or reduce them to a select few species that fulfill a fitness) and you're going to see lots of damage to other populations.