I’d guess mostly because of the storage space and processing power needed. I run my own Peertube instance for personal videos, and it’s quite resource intensive due to transcoding (making the 480p/720p/1080p quality options). These are needed for a smooth viewing experience, especially on mobile or slower internet connections, otherwise you’d have a lot of buffering waiting for the 1080p file to load. But creating all these different quality versions takes up a lot of space and a lot of processing power. And processing power and space requires money to keep running.
I’d guess mostly because of the storage space and processing power needed. I run my own Peertube instance for personal videos, and it’s quite resource intensive due to transcoding (making the 480p/720p/1080p quality options). These are needed for a smooth viewing experience, especially on mobile or slower internet connections, otherwise you’d have a lot of buffering waiting for the 1080p file to load. But creating all these different quality versions takes up a lot of space and a lot of processing power. And processing power and space requires money to keep running.