I honestly haven't noticed it, but maybe that's just my own ignorance. I'm a support main and looking through my match history (on my smurf because I came back from being unable to play since the start of season 1 and felt guilty using this account with 0 knowledge of the game), it has seemed that way now looking at it (except for one game where my team threw at baron, but obviously that happens). Maybe it's due to the importance of dragons now? I mean handing over an infernal/earth dragon is really going to hurt late game, and if your bot lane loses you effectively lost control of that area unless you kill the enemy bot lane. Even handing over a cloud/ocean drake is probably unfavorable (cloud is the least important imo, but I do see it's upsides since it lets me roam a bit better), since even the sustain/move speed can start to screw you in small ways. Most teams don't take rift herald (at least in my games, no idea about yours) which probably could give you a more equal footing with a losing bot lane, but games still aren't entirely predictable because, like I said, Baron throws or even Elder Dragon throws.