Honestly can't remember the last time I had a game with bots.
When I get games with low levels, they are often queued up with someone.
Keep playing. If those are the types of games you're getting, you should get easy wins.
Had a 26 ARAM win streak once because games just seemed easier than usual.
Also had 10+ loss streaks because of multiple quitters and trolls, along with bad games between.
Not saying 4v5 isn't winnable. In some cases, you almost have an advantage. Less feed, more experience. Just play smart.
But as soon as 1 of the 4 give up and quit or start trolling simply because its 4v5, then you're screwed.
Also, not everyone takes ARAM as a serious mode, so they just play to have fun.
I do too sometimes, but even if I'm building tank Ashe or AP Alistar, you know I still play to win.