I'm not sure that's as good an idea as you think. Even LE has designed ACME to ideally be replicated elsewhere. The big problem with having only one CA is that

I'm not sure that's as good an idea as you think. Even LE has designed ACME to ideally be replicated elsewhere. The big problem with having only one CA is that if they get compromised or go down, that's the entire internet. For good reason, it's not like you can launch a CA in a day, so we will always need a few horses in this race. Culling the herd isn't a bad idea, but without some diversity any issue could be catastrophic.