Probably. I only watch one streamer, and only occasionally.

That said, headcount shouldn’t need to scale much with more users. Look at Valve, which has ~360 employees and hit 33.5M active users, ~11M playing a game. Here’s some of what Valve does:

• hardware products, like Steam Deck and Valve Index
• Windows compat - Proton; granted, most of the people working on this aren’t Valve employees, but contractors Valve pays
• make games - not often, but there’s still maintenance work
• manage a CDN - not quite as much data as Twitch, but still substantial, and it’s certainly in the realm of not being a huge difference in terms of manpower to maintain
• Steam Link app - available on many of the platforms you listed
• Steam mobile app
• Steam app - Linux, Windows, macOS

So Valve has a similar-ish level of complexity with well under 500 employees. Maybe Twitch needs another 100 or so employees to manage the CDN, but surely not another 1500 or more.