Never I've seen anyone complaining of the compression artifacts while looking at a digital TV.
Streaming flac would theoretically take too much bandwidth.
You've obviously never watched Freeview or Freesat in the UK. Many channels are routinely bad (by which I mean that they are broadcast at a bit rate that renders block artefacts inevitable, before any transmission path interference), and the sport, in particular football on Channel 5 or ITV 4, is almost unwatchable.
2. budget is not the problem neither. Cause we kind of have the proper CDN network, server sources, etc, there is no much extra money to be spent for streaming flac file specifically.