NFS No Limits (NFS game developed by Firemonkeys) lasting for over 10 years is nowhere near to being a flop (despite it being aggressively and egregiously monetized). Many games wish they can last as long as 10 years like NFS No Limits did. So many games had permanently shut down in 1 year, 2 years, or 5 years (like with NFS World). Some games even permanently shut down in less than 1 year.
Also, Need For Speed is way more well-known compared to Real Racing. If you were to ask an average casual joe about both NFS and Real Racing, they are more likely to know about NFS than Real Racing.
Real Racing is a lot more niche in comparison to NFS. More people (especially with the casual gaming audience) know more about NFS than Real Racing.