Serving longform is just expensive. A single 20 minute video viewed 100k times end to end can easily cost thousands of dollars in CDN fees. Maybe $2k if using the per-minute streamed deal thorough Cloudflare, easily $4k+ if via AWS and with higher-quality video.

So in a future Nostr where videos can get those numbers, earnings from zaps or ads would have to exceed that amount, otherwise the creator is actually taking a loss (or someone else is on their behalf).