Not sure what you mean with reencoding for each client? AFAIK no major streaming does this realtime. They reencode the content once from source into a number of

Not sure what you mean with reencoding for each client? AFAIK no major streaming does this realtime. They reencode the content once from source into a number of bitrates and formats, put the result on a CDN and then use DASH/HLS/Smooth so clients can dynamically fetch and switch between them based on a manifest. If you do not do DRM you can probably get away with only using HLS or DASH and three or so bitrates/qualities. 480p, 720p and source perhaps? That might double your storage req and the one time encode effort, but running costs are the same (if not less because people will consume less bandwidth).