Arguably, it's already too late, in that there's an attack called “harvest and decrypt”, which means that if someone gets inside your system, they can grab blobs of encrypted data and just store them, and then at some time in the future, when they have a quantum computer, they can open that up.
For secrets that will still be valuable in 10 years, let's say, like military secrets or advanced industrial secrets, those things may already be lost. For other secrets, maybe not, but it is very urgent that we get post-quantum cryptography in place as soon as we can.