Video streaming is getting cheaper all the time. Bandwidth costs are dropping every year (substantially in most cases) and bitrates aren't keeping up (the few exceptions probably being AppleTV+ and BBC iPlayer which do 30-50mbit/sec 4K HDR streams).
You can do this for so much cheaper than AWS etc price for bandwidth. You can get 100gigE transit from he.net for list price $4500/month. Add probably the same again for colo + hardware (don't need much hardware these days to saturate 100gigE) and you can probably stream videos to 20,000 concurrent users at 5mbit/sec for ~$10k/month.
Another way would be to use someone like OVH who offers dedicated servers with 10gigE (supposedly 'guaranteed') for about $800/month each list price, without having to bother with colo and ip transit setup.
Obviously this is highly simplified as you will require encoding resource and storage, but again with someone like OVH you'd be able to spin up a lot of cheap boxes to do this. How much this will cost will depend on how many videos you get and how many views per video etc.
So IMO the actual bandwidth is a bit of a non issue. The far bigger issue is getting users to use your platform (marketing is MUCH more expensive than IP transit) and then having advertisers on your site. This is a much harder problem to solve and where the real barrier to entry is.
You can do this for so much cheaper than AWS etc price for bandwidth. You can get 100gigE transit from he.net for list price $4500/month. Add probably the same again for colo + hardware (don't need much hardware these days to saturate 100gigE) and you can probably stream videos to 20,000 concurrent users at 5mbit/sec for ~$10k/month.
Another way would be to use someone like OVH who offers dedicated servers with 10gigE (supposedly 'guaranteed') for about $800/month each list price, without having to bother with colo and ip transit setup.
Obviously this is highly simplified as you will require encoding resource and storage, but again with someone like OVH you'd be able to spin up a lot of cheap boxes to do this. How much this will cost will depend on how many videos you get and how many views per video etc.
So IMO the actual bandwidth is a bit of a non issue. The far bigger issue is getting users to use your platform (marketing is MUCH more expensive than IP transit) and then having advertisers on your site. This is a much harder problem to solve and where the real barrier to entry is.