Just because I find it humorous to reply to you after you have your tantrum, I also went ahead and humored your claims. I imagine you haven't posted actual proof because you can't find it yourself, which would fit nicely in my 45 (edited time to account for additional searches after initial post) minutes of dedicated research on the matter. Now, I'm sure you're going to say that I just don't know what I'm doing or have no idea how to search correctly so you can save a small amount of face by keeping that deflection to yourself.
The fact of the matter is, you claim there to be evidence that no one can find, so if you have access to this secret information that supports your claim, you should present it.
For some reason, I don't believe you have this information to post in the first place.
EDIT: I actually found something, though I guarantee it's not what you're pretending to have existed. It took some real Google skills to find it, with search terms one would not expect to need for something of this nature. However, what I turned up is hardly helpful and actually doesn't answer the question presented in this thread, though I'll continue this edit and post it here because, unlike you, I have no problem presenting information especially when it's such a huge pain in the ass to actually find.
Almost a full YEAR ago (as in, Sept 15, 2014), RiotLyte posted a very small bit of information where he claimed something was in the pipeline to allow players to restart a match where someone didn't reconnect. Clearly, that system isn't here yet and I can't find any information regarding any updates in this vein since the initial post. Plus, as stated, it doesn't answer the question for why no system is in place other than "we know it sucks", while plugging their LeaverBuster system even though that doesn't do anything for this issue.
Link to found information: http://www.nerfplz.com/2014/09/riotlyte-restarting-leaverafk-games-in.html Again, that information was from a year ago and still has not borne fruit nor has it been updated since.