As you and others point out well, nobody can know it all. My own solution to this is to (try to) spend some regular time learning, maybe keep a prioritized lists of possible future topics, and just try to prioritize tasks for the rest of the time in ways that will hopefully involve technologies with less churn to them.
But long-term, I have ideas for a generalized system of maturity models and known best practices, where a community can make interlinked lists of things to learn, that tracks prerequisites, and the best order to learn them in, with suggestions on what comes ~"next" at any given time, toward a specific learning goal. So, someone doesn't ever feel a need to stay up with everything, because knowledge is growing so fast anyway, just what comes "next" at any given time. With anki-like features built in. Something like wikipedia plus low-level computability of all the info stored. I haven't been getting as much done lately on it, (though I use it daily as a personal organizer), but I hope to in the future sometime. More on it at http://onemodel.org .
But long-term, I have ideas for a generalized system of maturity models and known best practices, where a community can make interlinked lists of things to learn, that tracks prerequisites, and the best order to learn them in, with suggestions on what comes ~"next" at any given time, toward a specific learning goal. So, someone doesn't ever feel a need to stay up with everything, because knowledge is growing so fast anyway, just what comes "next" at any given time. With anki-like features built in. Something like wikipedia plus low-level computability of all the info stored. I haven't been getting as much done lately on it, (though I use it daily as a personal organizer), but I hope to in the future sometime. More on it at http://onemodel.org .