Evidently, it is more popular. The thing is still in super short supply despite being in production for months now.
But I don't think the 5D IV being viewed as an incremental upgrade by some parts of the internet community means all that much. That's probably just the regular Canon thing. No hype around the specs on the internet, but when you read something from an actual user, it is usually very positive and somehow Canon has maintained a comfy advantage in market share despite offering the bare minimum of what the internet requested for years.
The R5 being such an aggressive push is simply uncharacteristic for Canon. I haven't read a Sony Troll post here in quite a while. It's almost like they have been obliterated. Looking forward to the R5s / R3 and R1 launch