A typical low Elo game
This is the kind of game I constantly see in bronze on my smurf account. Except that this time, it is on my main were I went from diamond MMR to low gold MMR after a losing streak. http://matchhistory.oce.leagueoflegends.com/en/#match-details/OC1/168407446/200842675?tab=overview
Typical game: We win every lane, and get a 8k gold lead and 2 level lead at 24:00. Free win? Nah... Instead of getting some vision, get dragons and nashor, push lanes, group and siege a turret... Players want to have fun with their lead. They roam around the map randomly, without vision, hoping to catch someone and get some kills. They die a few times getting caught... get a few kills... but who cares? They had a lead, right? This continues, until they enemy team catch 1 or 2 and take nashor, then a few turrets... then the inhib...
gg wp.
In LCS or high elo, games are shorter, and much less kill happen. Solo kills in lane are rare, they happen around objectives mostly, or in well coordinated gank when summoner spells are down. games end 10 kill each side. In low elo, games last ages, and games end 60 kills each side.