Well, people still drive even though driving is almost universally bad for you.  I mean, there's only a limited number of ways driving can turn out.

1) You are a pretty bad driver and yet you get where you are going without a hitch. 

2) You are a pretty bad driver and get in an accident and injur yourself.

3) You are a pretty bad driver and get in an accident that kills you.

4) You are an ok driver and you get where you are going without a hitch.

5) You are an ok driver and get in an accident and injur yourself.

6) You are an ok driver and get in an accident and kill yourself.

7) You are a good driver and get where you are going without a hitch.

8) You are a good driver but someone hits you and you are injured.

9) You are a good driver but someone hits you and you are killed.

10) You are any of the above but someone else hits you and causes no injury but results in damage to your vehicle.

11) You are any of the above and get stuck in trafic, causing your driving to take as long or longer than walking.

I mean that's 11 outcomes (with streamlining) with only 3 actually good outcomes.  The rest are all injurious or at least waste your time.  Three of them are lethal.  So when you go out on the road, you have a three in eleven chance that you actually get where you are going with no issues faster than if you walked. 

See why that kind of logic is not an accurate basis for analyzing risk?  A lot of things have far more ways to fail than to succede.  This does not mean that failure is necessarily more likely than success. 

All tongue-in-cheek aside, Demos are not necessarily beneficial or detrimental.  And they do suffer, as you said, from being unrepresentative.  The better idea for a demo is to do what Etrian Odyssey Untold: Millenium Girl does.  It IS the game, just the opening portion.  Your opening is designed to hook people anyway.  The use of the cliffhanger is highly, highly effective.  So having a "demo" that is just the hook part of the game (the beginning) could very well increase sales.  However, because of the other points in that video, this is still not giong to help consumers all that much.  Because if you do a demo this way, the game itself must be good.  Which means only good games (according to the quality assurance teams) will have demos.  Which means they won't help much with sorting out bad ones. 

On a side note, I think the new trend of having long running "betas" is an attempt to get the selling power of the demo with none of the backlash, as people are much more forgiving with a WIP usually than a final, purchased product. 

This is a VERY, VERY poor analogy. The likelihood of a good outcome when driving is much higher than the likelihood of getting in to an accident. The demo outcomes, on the otherhand, are pretty close in probabilities. Basically they represent three outcomes (demo is better than your game, demo is the same as your game, demo is worse than your game) for three types of games (good game, okay game, bad game.) Furthermore, the additional argument is made that the benefits of a good demo, good game combo aren't that great, and hence not worth the risks. Meanwhile when you drive you usually do so because the alternative is labor intensive, time intensive, or both and is worth the risks involved. Both are cost-risk-benefit analyses, which is what most companies do when making decisions. 

First, you would think I was joking.  Unless you think I ACTUALLY think driving is disadvantageous.  I don't.  But the bolded is the thing I call into question.  According to who?  There's really very little they can look at to prove that this is in fact the case.  Now I will say this:  the ad campaign blitz strategy is a safer bet though more resource intense.  And that's what it really comes down to:  demo based promotion *requires* more polish, more quality assurance, and may still be ineffective.  The ad campaign blitz can sell almost any game, polish be darned.

That's the thing.  Demos are not quantifiably reliable, ads pretty much are.  It's that simple.  The rest of the analysis is entirely superfluous. 

Aren`t demos still around? I`ve played some this gen and I`ve learned about games I liked/disliked. They`ve changed a bit, but they still seem to be around... o:

We'd have to wait for a demo patch for some games to even be playable, lol.

Demos are a thing of the past. Today, instead of getting some magazine with a demo disc, you get yourself PS+ or Xbox Live and get some full games every month. "But those aren't the games I want to try!", you might say. However, you also didn't have a choice which demos were on the disc back in the days.

With the heavy media presence today, countless reviews and videos along with things like share play, I don't think demos are needed anymore. It just eats into the already little time development teams have at their hands to make a game. So no sir, please no more demos. Let them rest in peace.

I mean, Nintendo has offered quite a few demos as of late. I've definitely done a few, but there are plenty I haven't touched.

I can understand that the "traditional" demo might not be compatible with today's way of making bussiness.

But I'm all out for demos like P.T.. That's the ultimate form of getting people hooked to an unfinished project. Whether they turn out dishonest or not, that's up to the developer to fullfill the demo's promises.

Interesting, seeing that demos and trailers are present in stores to sell consoles to the consumer first hand. They aren't resting in peace...they are only being used to sell consoles. The people who give us our reviews and previews online get exclusive   access to them and then tell us how good or bad the games are rather  than us being able to form an opinion. Think of it as democracy. Companies  allow representatives who are given hits, ratings or views to and they in turn give a subjective  response in only the most human way possible. That's just the thing these days. We should have access to what these people have played even if it's late. Nintendo and Sony have done a great job with demos at best buy. It's one of the  things that convinced  me for the first time in years that the wii u was for me this gen.

Yeah, but it's not like we got to play every journalists demo there was in the 90s. Also, there is more than just traditional gamesites. With Youtube, Twitch and whatnot, you have countless private people showing the games so I'm pretty certein you can form yourself a pretty good opinion on a game. 

I just think that demos are not worth the effort these days. What makes more sense is what Sony did with the full games you could try for an hour. That's more than enough to get an idea of a game and it doesn't need extra work. It's also completely hones because you later get exactly what you saw. That principle could get also more interesting with PS Now, where you don't even need to download a game before playing it. You just play instantly. Streaming might not be perfect in every way, but it's the way to go for trying out games. I think that's where the future of demos is. It already worked flawlessly for PC on Gaikai some years ago. It may still take some time for mass availability, but it will be there sometime. The need for traditional demos is gone for good, they won't come back. Just like passwords won't come back or games on modules.