Companies dont want you to download it... They would much rather charge you every time you enjoy it.

If I'm not mistaken, these days (unlike in old days with RTSP)'streaming' videos are chunk-downloaded instead.

BTW, VLC can read videos while they are being downloaded just fine. It can also stream videos from, for instance, YouTube. Also, youtube-dl is your friend.

you dont even need to download it because most players can access an url just fine. mpv with ytdl integration is my goto for viewing sites that just wont give users access to the video-url (youtube/twitch/vimeo...)