I personally thought the first tower gold was a big reason on snowballing, which could be the reason if not the main reason on why.
Another which could just prove how stupid and/or crazy I am but not going to lie as soon as the first tower gold meta/patch came out every champion felt 10X stronger on the offensive side of things, their abilities felt stronger and did more damage but their HP and armor felt weaker. It just seemed it to me.
Back to your point and argument; Riot is trying to speed up the game in a way to compete with Call of Duty and Overwatch. Those are two quick games in which people have/are going over to those instead. I don't know the #numbers or anything but games were around 40 mins for me on average back in 2014 but now games have been around the 25 min mark for the past year or so.
Good post, but Riot takes Q's from the LCS players and what they want, need so many arguments could be from Bjergsen, Jensen, and other pros instead of Riot themselves most times.