Speaking ahead of the PGA Tour's season-ending Tour Championship, which tees off at East Lake on Thursday, McIlroy said the increased FedEx Cup jackpot on offer definitely wasn't his main source of motivation.
"If the FedEx Cup wants to create a legacy that lasts longer, it doesn't need to be about the money," said the Northern Irishman.
"It should be about the prestige of winning an event that you'll be remembered for.
"I'm not saying that money is a bad thing, it motivates a lot of people, but I think for me and my competitive spirit, I want to win the FedEx Cup for a lot of different reasons.
"Look, it would be nice to win on Sunday and be, oh, I'm $15m richer, but at the same time I'll get more satisfaction from winning the golf tournament and playing well.
"I don't think the money needs to be front and centre, because I don't think that's what the fans care about. Players might care about it and we want to be rewarded and paid for what we do, but competitively it's not about that. It's about trying to win golf tournaments."
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McIlroy also admitted he wasn't exactly convinced by the new FedEx Cup format, which sees players given a stroke-based advantage at the start of the Tour Championship based on their position in the standings.
Points lead Justin Thomas will start on 10-under, for example, while McIlroy will begin the week on five under, already five strokes off the pace.
"Is people starting the tournament on different numbers the best way to do it?," McIlroy asked.
"I get it from a fan experience point of view and I get it from giving guys that have played better throughout the year an advantage.
"At the same time, it will make it sweeter for a guy that starts at even or one under par and goes all the way through the field and wins. Come back to me on Monday, and I'll tell you whether it's worked or not!
"Depending on where you come into this tournament, you've always got a different perspective. I know it's definitely a simplified version and format and people will understand it better.
"I think it gives more guys a chance to win this week. If you look at it just from that lens, it probably is better this way."