I do not think it will implode though - what is going to replace it?
1. I think it is used for too many things which may need different approaches. For example, a central authority to sign certificates for various software updates from various vendors is not necessary, they can issue own certificate, user can accept it and install by default with the app itself. There are many such scenarios where the scale is more pgp-like than ssl-like, I think the question "what do we try to achieve here, security-wise?" is not asked seriously enough when a system is designed. "This is how it is done" is the answer by default in too many places. It takes the burden of thinking out of the box from you, but it also means potentially great ideas do not pop up, let alone make it into the mainstream.
2. Nobody and nothing is irreplaceable. The cemeteries are full of irreplaceable people, how can we seriously think a flawed security model cannot be replaced? There are attempts with blockchain and other technologies derived, quantum keys embedded in light and other preposterous stuff for many, but if we do not try, it will never happen. Before Tesla (both the man and the company) many people said "it will never happen". Some still say that... Both Musk and Jobs used existing technologies in a different way, combined, beautified, made appealing... The result is a revolution in progress, even tho they did not actually invent much.
3. I say this for a long time, we have the technology, the will and the tools to build a "layer 8" internet, entirely encrypted, floating filesystems, even VMs, a virtual home for everyone, powered by the shared resources of many, bits and pieces of traffic, storage and cpu, completely anonymous, uncrackable without actual police work (infiltration, social engineering, undercover agents, etc). As that is done for one purpose, the same "Layer 8" can be used for the complete opposite, absolute identification and message signing over a completely encrypted p2p connection.
Absolutely everything needed is out there (sure, not specifically designed for this, but trivially simple to adapt), need the organizing to make it happen in spite of Big Corporations, Cults and their minions, the nation states.
