Player attitude has not changed.
If there is zero reward why stick around?
For fun? How many people play every game over and over and over and over and over and over just for fun without any hope for reward?
Zero reward means they will just abandon the game and eventually stop queuing.
This has already been proved when warzones only rewarded the winners.
Theres still rewards though. You have your end of season rewards as well as earning ranked commendations. I can't imagine even the worst of players not being able to win a handful of games in a week.