Is it expected that I should stop by the ever-changing Wikipedia before posting a question?
Yes, absolutely. Or at least something where the answer might be, e.g. doing a google search. And really, is that too much to ask? The stackexchange networks goal isn't to be an answer machine for anything you might want to know, let me quote from the tour:
With your help, we're working together to build a library of detailed answers to every question about electronics design.
There are two important points here. First of all, it is to build up a library that answers things, not a machine to answer questions people might just now have. You say yourself that you did a rudimentary check that it is not a duplicate. rudimentary in my ears doesn't sound quite the same as enough. But anyways, the second point is, that the question is expected to be about electronics design. So although we generally take that very liberally, as Olin said, it is not a good fit for this site. You basically asked for debunking (or confirming) a marketing claim. There is a whole own stack (skeptics.SE) for this.
More from the tour:
Focus on questions about an actual problem you have faced.
Well, what electronics design problem do you have? Had your question been "I am building a world enslaving robot running on solar power, which motor type should I use for maximum efficicency, brushed or brushless?" then this would go more into the direction of this site. Still not good, but unlikely to be closed.
Include details about what you have tried and exactly what you are trying to do.
So here we get to the point of prior research effort. We expect you to have tried to solve the problem you are facing. And we expect you to tell us about that effort. Rarely we need evidence (though sometimes it is good to show some) and take your word for it, but doing some research and trying a few minutes on answering that question yourself not only gives you some more insight, it will almost always enable you to ask the question in a more specific way.
A quick look through the wikipedia article tells you at least these basic easy to understand facts:
- Brushless is a quite new thing compared to brushed (1886 vs. 1962)
- Some limitations of brushed motors can be overcome by brushless motors
Ok, so lets get to the maybe not so easy understandable facts:
- Brushless motors offer several advantages over brushed DC motors, including high torque to weight ratio, more torque per watt (increased efficiency), increased reliability, reduced noise, longer lifetime (no brush and commutator erosion), elimination of ionizing sparks from the commutator, and overall reduction of electromagnetic interference (EMI).
- When converting electricity into mechanical power, brushless motors are more efficient than brushed motors. This improvement is largely due to the brushless motor's velocity being determined by the frequency at which the electricity is switched, not the voltage. Additional gains are due to the absence of brushes, which reduces mechanical energy loss due to friction
There we have tons of points to hook into to make up for a good question and show prior research effort, and that all in under a minute! You could ask about all of it, but then it is clear that things get too broad, as we generally focus on one point per question (remember we have only 30k characters for an answer). So now comes the point where you really have to ask yourself what it is that you are interested in. Do you want to know why they develop more torque per watt? Do you want to know why determining the velocity by frequency instead of voltage is more efficient? Ask those things! In several questions, not all in one (unless they are really just the same side of two medals), and not all at once. Ask one thing, try to understand it, then see if this doesn't tell you already something about the other thing.
Let me comment on some other things you said:
- alienating novice users and enthusiasts ("Silly question! What a noob!")
If you are truly an enthusiast, you would not ask silly basic questions that could be answered by a two minute google job. The very nature of an enthusiast includes actively searching for answers. Also this site is (again from the tour) for professionals, students, and enthusiasts. Not for hobbyist novices that want a handhold for plugging together their arduinos. Yes, we have a quality standard for answers and questions that have a quite higher bar than "what will happen if I poke my finger there?".
- losing out to other information portals like Wikipedia which will have basic information
Since when is this a competition? This site starts where wikipedia ends. We have the means to focus on details, ask for lengthy explanations of single facts that only got mentioned in half a sentence on wikipedia. Both are necessary, needed, and everyone who participates here should be willing to add knowledge there too.
- becoming an unhealthy place to share ideas and concerns. Quite frankly it feels hostile
Seriously, if it does, then good. This will make everybody think twice about what they say and ask. The goal isn't to attract as much people as possible, it is to attract as much good content as possible. It is not a place to share ideas and concerns. There a other places for it.