Virtually no deletion arguments conclude with a merge, though. Typically the information is completely lost, no matter how well cited it is. Which makes the verifiability argument bankrupt as well, at least as a defense of what actually happens on Wikipedia.
If the verifiability argument were sufficient, the notability policies would all be scrapped and deletion policy would round down to "delete articles which don't have any verifiable statements in them, merge articles which are less than two or three full paragraphs long". Which, incidentally, was more or less the radical inclusionist platform back when I wasted time on Wikipedia.
I wrote a big long comment about a year and a half ago where I supposed that the problems probably boil down to "editing as sport" and "status seeking quests for adminship". Both lead to situations where editing decisions are made in a slipshod fashion and then defended to the death to avoid losing points in RfA's.
Deletionism is not one of the things that is broken about Wikipedia. Deletionism makes absolute sense. Wikipedia owns the Google SERPs, there is tremendous incentive to paste up bullshit articles for profit, and the sheer volume of crap --- take this from someone who spent 4 months patrolling AfD --- is staggering. The "pure" deletionist ideology is harsh, but it ultimately serves the greater good of the project.
In every one of these debates, I see people lose sight of the fundamental point of Wikipedia. It is not, as many people believe, a repository of all human knowledge. It's an encyclopedia. The point is not to have all possible articles. In fact, that's the opposite of the point. The point is to have only good articles, using nothing but volunteer work.
I too am done wasting time on Wikipedia, and I'm pretty grossed out by what happens when you look under the rock that is the Wikipedia: namespace. But I respect the project itself. It is tremendously, staggeringly successful. It is clearly doing something right.
But for several years, up until, oh ~2005 or so, Wikipedia was on the path to becoming the repository of all human knowledge. Many people, including myself, found that to be extremely valuable, and exciting.
Why don't we get to say that the fundamental point of Wikipedia is to be an aspiring repository of all human knowledge? Asserting that the reason for these policies is that it's [merely] an encyclopedia [more or less in the traditional sense] is self-fulfilling rhetoric. You say "the point is X" but I say "the point was Y, and could have continued to be if certain people didn't establish turf and assert control."
From my point of view, Wikipedia was on the way to being something much more than what it is now, and value was lost.
"Imagine a world in which every single person on the planet is given free access to the sum of all human knowledge. That's what we're doing." --Jimbo Wales, Slashdot interview, 2004
If the verifiability argument were sufficient, the notability policies would all be scrapped and deletion policy would round down to "delete articles which don't have any verifiable statements in them, merge articles which are less than two or three full paragraphs long". Which, incidentally, was more or less the radical inclusionist platform back when I wasted time on Wikipedia.