It isn’t, but then again, in 1995 we might have said the same for expirations in 2015, and yet so, so many poorly managed CAs were expunged in the past 5 years.
A healthy root store would set revocation at a much more aggressive period; say, every five years. Every three years, the CA applies to have their new root trusted, which gives two years to distribute that root to clients that need it, while having the old root sign the new root, to support an immediate transition to the new root. Among other things, this encourages a more robust and healthy CA ecosystem, because you don’t end up with lopsided balances based on “who has the oldest root.” That imbalance encouraged poor behavior which got CAs distrusted, in the past, because they behaved in a manner that assumed they were too big, by virtue of being too ubiquitous, to fail.
