There's actually less to learn than you might think. The vast majority of magic comes down to a handful of basic principles. What the magician adds is showmanship, and a butt-ton of practice.
Once you know the basic principles, you can usually figure out the tricks. It might take multiple viewings -- which is part of the reason that it's less impressive to explain the trick. Once seen, it's hard to un-see it. Even performing the same trick twice identically gives the audience a huge opportunity to figure out what to look for.
What the magician really wants is your respect for how much work went into making it work out. The trickiness is usually not that big of an insight. The hard part is that it takes hours and hours and hours to learn to, say, deal a card from the bottom of the deck while making it look exactly as if it were drawn from the top. It's taking a deeply unnatural motion and making it look as if it were a different, natural motion.
So from the magician's point of view, you really would be disappointed to hear "All I did was to put your card on the bottom of the deck and deal it out." It's easy to describe and hard to do -- the least rewarding kind of skill.
Most magicians already know how everybody else's tricks are done. Stealing tricks isn't really the issue. What they really want to do is steal the trick and make it their own -- which may involve elaborate construction. Many magicians are pretty competent engineers, and the big acts all have a team of engineers in their workshop.
So really, if you want to know how the trick is done, go read some magic books. There are fewer secrets than you think. Once you've got the basics, watching a magic act is like solving a puzzle. It's more fun than having them tell you the solution. And you can really respect the effort that went into making it happen.
The point isn't that I'm necessarily completely stumped by a trick (although that does happen), or that I can't enjoy a trick without knowing how it works, but rather that knowing the techniques required to perform the trick is additional enjoyable content to me. It's really no different than watching behind-the-scenes or visual effects breakdowns for a movie that I enjoyed. It's an additional piece of content that I enjoy and it almost always enhances my appreciation for the original content.
> So from the magician's point of view, you really would be disappointed to hear "All I did was to put your card on the bottom of the deck and deal it out."
If the magician thinks that I would be disappointed, that's precisely the misconception I am trying to point out. I absolutely am not disappointed when I hear such explanations.
I do know that when I explain tricks to people, they're often disappointed. I often hear, "Oh, they just lied to me." Yeah, they did. I mean just really bald-faced lies, not sleight-of-hand or illusions or misdirection or other cleverness.
I immediately lost all interest in magic.
Oh, here it is: https://www.thegreatharryhoudini.com/vanishingelephant.html I misremembered.
I am pretty sure it's mostly "I don't want someone else to steal this." Generally, I'm pretty unconcerned about telling people unimplemented ideas. If they want to rearrange their life to "steal" my idea, good for them. But they probably won't be able to execute it as well, so it's not really a concern I have. But, magic is tough... you want to have new material for your acts, and if someone beats you to the punch, you don't get paid. So I see why magicians are paranoid. But if we get a new generation of Penns and Tellers, I'd personally be happy.