Some people will do that. Even if you aren't a duo, you can still have people chatting in game and decide to honor each other. Also certain roles (mid, adc) and high kda tend to equal honor. This holds even if another role/player clearly deserves it more. In addition, many people just choose not to honor anyone because either no one played well, everyone played equally well, or they just don't care.
Take a look at the match in this post and tell me who - if anyone - deserves honor.
https://boards.na.leagueoflegends.com/en/c/gameplay-balance/EgA7V95E-you-have-feeders-i-get-them-almost-every-game-mid-and-bot-1191-combined-at-19-minutes-help-me?comment=0000
(shameless plug)
As far as I am aware, the sejuani and myself each only got one honor and some people didn't give anyone honor. I gave it to her because she enabled me to split and group to strategically stall out the game and get our carries back into it despite their combined 1/19/1 start to the game. I assume she gave me the one honor I got. One apiece after the two of us carried a game for 30 min when we in all logic should have lost in around 23 min. Now THAT is a sign of broken honor system and probably matchmaking too. Sure cait looks like a god via her kda at end of game and blitz had some nice cc in teamfights, but all that only came about because sej and I 2v8 stalled the game forever and made good shotcalls that the rest of the team (mostly) followed. Cait got that kda because in teamfights no one could touch her long enough to do more than half her hp in damage because sej and I simultaneously tanked all enemy burst, cc'd them, and blew up a carry or forced them out of the fight within the first 2 sec.