&gt;we become experts at many things, but at the cost of flexibility and speed of learning<p>It&#x27;s partly <i>because</i> you are an expert at a unique combination of many things that you have great irreplaceable value. This is threatened by aging diseases even before you die.<p>Also I don&#x27;t think that more knowledge makes it harder to learn.
This would be true if knowledge was purely about breadth. However it&#x27;s really about explanatory <i>depth</i>, and depth ultimately wins. For instance, your mind has formed many connections between those aforementioned different fields of expertise, and some of these ideas reach into yet more fields.