Many don't. I am a recreational sailor who took classes and then spent a couple years sailing under the tutelage of more experience folks before striking off and buying my own very inexpensive sailboat. I believed this was the natural course of things, logically, right ? Wrong. Once I got to my first marina I was stunned to find out how many people don't bother with lessons before buying a boat, don't put ardent research into the matter, and just learn what they happen to learn from other people. It's not a rare amount of boaters like this either, at least at my marina. To make it worse, we all know that map reading is just difficult for some people; I'm sure the pilot community all knows folks who struggle with navigation and map reading; it's the same in the boating community of course. Some actually go out without charts at all, just using the channels to get into the bigger waters, and most of us actually don't use paper charts at all anymore, opting for electronic charts. Many of these are highly updated and have community inputs as well (because we do have to deal with things like storm debris, wreckage and other "fast moving data" things. However, this will be stunning and it should be - I have come across multiple owners are rather expensive boats who literally didn't know how to even use their electronics. Not once, not twice, multiple times. One time I was sailing with someone on a 40' boat and became the defacto helmsman (a place usually reserved for the owner) because I could mash the buttons on the system fast enough to figure out how it worked, and pull up the appropriate charts, radar, and position signalling data. Wish it weren't true, but it's true as day. The recreational boating world is essentially completely unregulated, and there are some people with boats whom in my opinion absolutely shouldn't own boats.

In regards to your anecdote about the captain: I rarely use charts when I'm sailing because I know my local waters quite well, where the obstacles, spoilage and shoaling are, and can easily navigate several hours in any direction without them. But, that's me. I studied my charts for quite a bit before even getting on the water, and I've learned the various depths and right now I could probably draw you a fairly accurate chart of the region surrounding my marina by memory despite having not sailed in a year. Many good, skilled and experienced sailors are like this - but that same experience and skill also means that we absolutely consult the charts when in new areas.

Also see my other comment about "Captain". They are not captains; that's a legally reserved term for USGC licensed people. They are skippers or just boaters and sailors. When I am on someone else's large boat and need to communicate clearly to the person in charge I will use "Skipper" or just "Skip"