Why does aram feel like a cash grab?

I understand free week champs will be selected but why is it that 4/5 games I have a free week champ? And 80% of people in my games are playing free week champs? I mean seriously I have played like 15 arams today and every game had a zilean, 2/3 of the games had talon, 2/3 of the games had lulu, 2/3 of the games had malz and half of the games had ashe, graves and lulu. Why do free week champs have a higher chance of getting picked? And its not just because I am low level. My level 30 friends a lot of which own 90+ champs notice they get free week champs more then they get non free week champs regardless if they own them. My friend who almost exclusively plays aram notices that champs are much more likely to get picked in aram if they are not free week. Rerolls are more likely to be free week champs as well. He has noticed that a lot of times when he rerolls a free week champ they end up on the enemy team a lot of the times. This seems more like all free week all mid then is is all random. This makes it feel like a cash grab because there is literally no other reason that free week champs should have a higher chance of coming out other than riot trying to get people to buy the free week champs.

Edit: This just proves how ignorant the league of legends community is, I make a valid point and just because you don't agree with it you downvote. It't not like I was flaming. I even made a point to include that my friends who only play aram who own most of the champs run into the same issue.