When I looked into it they’re mostly using mirrorless cameras like the Panasonic Lumix GH5 or the Sony a7siii with something like the elgato camlink 4k to get clean output.

The Sony A7SIII sensor is just as good as it gets outside of cinema rental market. But certainly any post 2010 APS-C or bigger Sony should do to reliably differentiate from consumer webcams, all you need is a bit more light. Maybe get a prime lens on top and that's it, if you're willing to deal with a HDMI capture setup. The specs of some 4k drone gimbals are also impressive, also using mostly Sony sensors, those might be the next best thing to motorized gimbal setups with optical zoom lens, like those used in telepresence sytems:

https://news.ycombinator.com/item?id=25511682

Yeah I think you're right.

I got the LG Meetup for my living room at the start of Covid and it's mostly an overpriced disappointment. I also had to get the external mic because the built in one doesn't have the range advertised (they actually advertise two different numbers).

I wanted something I could just plug into my TV PC to use for video chat. The Rally setup has the PTZ camera I wanted, but requires two external boxes which (as far as I can tell) serve no necessary purpose other than bad design.

In hindsight the PTZ rally camera with an unrelated third party mic would probably have been the best bet. I would have thought El Gato would come out with some high quality webcam eventually.

> Which makes me wonder, what cameras are Youtubers using?

iPads are taking over. You can get pretty amazing image quality with a new iPad Air or Pro. You can even get rigs with gimbals, lighting, and external mics for almost any budget.

How fast can the hardware market typically respond to a sudden and potentially short term increase in demand like this?

Depends. Inventing new products probably 1y out. But ramping up production on an existing product to a new category should have happened already.