Aside from spam and pages that exist merely to advertise products/companies/etc, it seems like most are those examples aren't necessarily bad, and if no one is using the articles, it's not like a huge number of static text/image pages are going to be a massive drain on resources.
Perhaps the answer to this is to allow for "personal" wiki pages that can be approved for inclusion into the main body of Wikipedia.
From my perspective, I would rather have lots of extra fluff in Wikipedia that I will never see rather than whole subjects being deleted from the site on the whims of a few jerk admins.
Edit: And you seem to be defending the deletion of BBS history under the guise that "Else spam would be everywhere!" which isn't an argument I agree with.
The problem with the unused articles is slightly subtler than "it will use up our hard disk space!"
A friend of mine recently created a Wikipedia article for one of her own economic theories. She is not an economist, and as far as I know has never studied economics. The theory is loosely based on the work of one economist, but the sources she listed included her own blog, that economist's work, and newspaper articles--not articles about "the XYZ Theory," but articles about events she believes are relevant to her theory. But the end result was a reasonably well-written article, with plenty of linked citations (which would appear relevant to anyone not paying close attention), about a theory that does not exist. And because the article got so little traffic, she was the only one editing it.
The thing is, when she linked to that article from her blog and social media profiles, and from other tangentially related Wikipedia articles, suddenly that theory seemed to have some validity that it hadn't had before. And googling "XYZ Theory," which would have gotten 0 results the day before, now got a handful of results. All of them were related to that article or her blog, of course, but someone casually searching for information might just click through to the Wiki article without noticing.
The point is, articles about non-notable topics aren't just irrelevant. They're of much lower average quality than the rest of Wikipedia because they have much less traffic and many fewer potential editors knowledgable about the topic. They're more likely to have factual inaccuracies, more likely to be biased, more likely to just suck. And it'd dramatically reduce the confidence one could have in any Wikipedia article about anything one hadn't heard of before, because you might be its first viewer.
Wouldn't it be a good thing as that would open our eyes to the fact that Wikipedia articles are really not reliable at all? I don't see how a fast deletion mechanism makes the articles more reliable.
The proper solution seems to be to let the articles stay, and learn that they don't have much weight.
And if deletionism is a reaction to SEO optimization, as the other comment states, it is even more of a tragedy. Really, we have to delete articles for fear of somebody getting an unfair SEO boost? Again the solution seems to be to just lower the impact of links from Wikipedia.
This is an excellent anecdote about how Wikipedia's existence gives unsubstantiated weight to those who choose to spend the time writing stuff there.
We all say "sure, we know not to trust wikipedia" but when it's the first google hit for many topics, can you really pretend you always read it critically?
First, I'm not "defending the deletion of BBS history". It's telling that merely trying to put what's happening on Wikipedia in any kind of balanced perspective counts as taking a side here; it shows how artificially polarized this issue is.
Second, there are clear practical reasons why it would matter if the examples I provided survived as Wikipedia articles:
* The overall perception of Wikipedia's reliability --- which, in reality, is comparable to that of Britannica's for most subjects, and particularly for subjects that are important in the context of traditional encylopedias --- would be sharply diminished.
* The encyclopedia would be full of overtly false information, since no contributor to the project would be able to verify any of the information in those articles.
* Wikipedia would be ruthlessly gamed to get pages to the top of Google SERPs (it already is, and a lot of deletionism over startups and individual people is a reaction to that).
* The project would lose huge amounts of time to mediating squabbles over article name real estate as different garage bands or local volleyball teams argued over which should be the first listed name for their project.
Perhaps the answer to this is to allow for "personal" wiki pages that can be approved for inclusion into the main body of Wikipedia.
From my perspective, I would rather have lots of extra fluff in Wikipedia that I will never see rather than whole subjects being deleted from the site on the whims of a few jerk admins.
Edit: And you seem to be defending the deletion of BBS history under the guise that "Else spam would be everywhere!" which isn't an argument I agree with.