The R5 is a great camera. That it can have such great photography and video capabilities in the one camera is amazing. That you can record 8K at all is amazing. Great too that Canon is doing firmware upgrades for it. At the same time the video capability of the camera must be the biggest overkill in a consumer product ever. I'd say most of the footage taken with it will never be processed and never seen in 8K. I think the video quality has gone along way through the path of diminishing returns. I think once HD was achieved thats about all was required. Better video doesn't require better image quality it needs better content, locations, scripts etc. The same thing videoed in HD and 8K is more or less the same thing to the viewer. Given the lack of 8K devices most of the output ends up at HD at best. There are not too many devices where its main selling point is practically irrelevant for most of its buyers. It's probably partially that its hard to emphasise improvements from the photography perspective. Improvements while good are marginal and perhaps not eyecatching.
I agree with some of what you have said, but the main selling point for most of us on R5 is
NOT the 8K or HQ video modes. I think the marketing was aggressive on video (why not try to get more customer base) and people are easily manipulated to emotion before thinking.
I'd actually like to see a survey if it were possible, but speculate the vast majority of actual R5 owners are not vloggers and other video gear heads. The R5 is a MILC 5D5 stills camera with very good basic 4K30 and some limited duty extremely high quality video; it cannot be said enough times what this camera is and is not. People have to look at the facts of the camera and not get tricked by big bullets and marketing, nor by the legions of moronic reviewers who make fallacious statements every other sentence. I cannot be the only one who skips commercials and doesn't read marketing or listen to youtube morons, but goes right to datasheets... Or if needed, rents equipment to learn about it? I guess that requires effort or an investment of time or small amounts of money, and its no effort or investment to just watch some talking head and parrot what they "found" on their ad revenue or sponsored "channels".
To say that the HQ video (here I mean anything above HD) is never needed is not true. There are plenty of legit uses for 4K60 and 120. 4K60 produces smoother footage, even presented at 1080. 4K120 is for slow motion. 8K and 4K can be cropped heavily to 1080, or downsampled for higher quality at the lower resolution. So there are many real uses where quality increase over HD is significant even if finally presented in HD, and many things that just need high frame rates. A lot of TVs and monitors support 4K and 4K is even noticeably better on some laptop displays despite all the distance charts you'll find stating it is impossible to tell the difference- you can indeed notice it. The best use of the high frame rate modes are motorsports, airshows, sports, animals, action etc. Unless one is paid to document entire events of that nature, the limits in R5 should be no big deal, and if someone is a pro or even a serious amateur instead of a whiner focusing on negatives, they should already have adequate gear or look to a dedicated video camera instead of complaining about the reality of the R5. Most amateurs and vloggers (who seem to be the loudest and least educated of everyone talking about the R5) don't need what they think they do, because frankly most of their content sucks, especially if their content is about making content, not actually making content. That is where I strongly agree with you- good content is planned, has good techniques, locations, scripts (when not spontaneous), etc. A good 1080 production will be way better than a bad 4K+ one.
Personally I love the R5 for stills and the basic 4K30 will suit my needs the vast majority of times I would need long video record times or a reliable 4K video mode while shooting long stills events that also heat the camera. In the rare event I need more, either I will rent, or work with the limited 4K60/120 since I shoot short somewhat planned clips. My professional Sony NXCAM (just sold) that I used for weather stringing to media outlets, and infrequent documentary and interview work still only had 4K30 and a small 1" sensor, yet I hardly considered it unusable all the sudden like all these childish fools who follow the latest youtube trends. It did become redundant and didn't have much going for it the R5 cannot do better, so it paid for a large chunk of my R5.
Interviews and most docile (non action) events in 4K60 or over sampled is in my opinion completely not needed and just looks more smoothly boring. Most of the people who think they need the best with long record times in a tiny MILC simply don't; but they have become attached emotionally to having to have the best or not be told no. These are the types who change brands with loud fanfare all the time or throw a tantrum about not getting it all in a tiny cheap body instead of just buying professional grade dedicated video tools that work for them and moving on. They are the same people on dozens and dozens of forums and youtube channels posting completely unsubstantiated cripple hammer gibberish and they think they are 100% right but skipped all the logic and thinking and proving and learning about electronics. Professional vs. childish behavior, and the mob mentality is well established against the R5 and Canon now. 4K60 and up is only recently possible in MILC full frame but 4k30 is somehow unusable trash and any limitation is unacceptable. It boggles the mind, and I cannot even blame some sloppy Canon marketing for this- I think people are going crazy, genuinely crazy, as irrationality is now mainstream.
I am rambling on yet again, but this is the depth of discussion that should be being had, instead of whining toddler speak accusing Canon of cripple hammer this or that, or saying thermal timers are fake with the most pathetic "proof" by amateur tinkerers who think themselves engineers. Sometimes, you do have to do the hard thinking and learning to be taken seriously.