...hardware capable But software limited...
This assumption is what has so many video/hybrid shooters up in arms. I'm not so sure it's an accurate assumption.
It's one thing to be able to shoot for hours once you override the safety restrictions. It's another to operate it like that day after day, year after year...and have it work as well four years down the road as it did on Day 1.
Canon may very well have put more conservative limitations in place than needed, erring on the side of longevity. Remember, Canon also plans to support the products, not just sell them. It's in everyone's best interest to find the right balance of capability and long-term reliability. After all, if running it hot cuts the life of the camera in half, it's no better than having to buy two cameras with current limits.
As Gordon Laing passed along from Canon reps, the R5 has THREE temperature sensors (two internal near the AF and sensor area, and one for ambient temperature). It uses all three, in combination with timers, to govern time recording limits. I think it's quite a leap to assume that any limitation on recording time is strictly an unnecessary software limitation. Why even engineer the multiple temp sensors if you're just doing some cinema-line-protecting-cripple-hammer-funny-business via the firmware?
PS: Anyone else notice that the firmware update allows you to enable the heat warning when recording externally? Why would someone want that? Oh...perhaps there's the real possibility of causing heat damage to the camera when recording externally because heat is still an issue...just one that was not managed when recording externally (until now).
Okay...going to bed because it seems it's not out of my system yet. Eh, Baron_Karza?