Possibly depends on camera as my R outputs at 720p (@ 30p 10MBs) via the canon webcam software and agree there is a point to do that still as it looks fine for webcam style use vs the webcam I have around somewhere and the better noise and low light performance, out the camera colour, control over exposure etc, better DR and so on means it is still not bad idea for just the odd call to family where video is needed (oft just audio is good enough for me and I do have significantly better than average setup for that so I usually wont bother with video). I don't need amazing IQ and a proper vid streaming setup would be stupid. I mean I can get better using likes of elgato camlink and so on but for most that is surplus to requirements and good enough as is.
I think this is a none issue as anyone who NEEDS significantly higher streaming video quality is better served with a proper setup which isn't a dslr/mirrorless stills orientated camera including hybrids aimed more at stills than video exception being likes of BPCC. Thus the use of such cameras as crappy res webcam alternatives is pretty much fine and compared to pro's it isn't apples to apples as two totally different needs and roles. For instance my cousin when he is on set uses real camera, on a rig with full cage and all kinds of stuff bolted on yet on his comp to speak to family he'll use either the webcam built into his laptop or a cheap logitech c920 hooked to a desktop because his work setup is simply not the tool for that job, they are two totally different needs regardless of if folks have access to the gear.
As far as streaming video folks who actually need the video IQ most I know personally don't even use the videocentric hybrid ILC's with clean HDMI out or adapted options like camlink but rather they use lower end cine cams such as C100 and C200 at minimum. Although I know two using higher end they own them for other work related reasons and didn't buy for that setup and simply use for streaming since kit is doing nothing during current restrictions and lockdowns and they relegated their streaming A cams to running as a secondary B cam such as for overhead that they previously used hybrids in that role. Again for those who need that they are after features that would be a disadvantage to regular consumers for use as "normal" webcam role since they oft output in clog (or equivalent for none Canon folk) and apply their own lut and using separate audio solution thus need the xlr interface and so on thus that isn't what most who need a simple webcam are looking for and conversely those "features" are cons not pros.
The parent is missing the point you made of good enough for purpose imho. They are totally different needs. One of my pet hates is the low resolution "pros" use arguments I see in a lot of areas when oft it isn't apples to apples to the none pro use for such tech. The usual car analogy would be it seems akin to saying "F1 drivers don't drive regular 4 door family cars, real pro's use race cars" when sure not if they are at work setting times on the track. Doesn't mean that applies to the best car for taking the kids to the beach nor going grocery shopping for the family and such pros oft use the same "none pro" car for those roles.