Naïve startup idea?
Rust: Considering the small number of players in this market (zoomwebvideo.com, wistia.com, jitrinc.com, tikilive.org, veevu.com, etc.), you might actually find a market for this service. The competition is quite varied in focus (example: JITR likes subject matter experts, Wistia likes enterprises), so finding a niche in there and doing it great is, IMHO, worth doing.