http://www.slate.com/blogs/screen_time/2017/12/21/why_can_t_i_stream_muppet_babies.html

The witty animated series can only be found these days in VHS or DVD releases that don’t contain every episode, or in grainy YouTube clips.

Id say the majority is not available due to extreme licensing issues from other properties that were featured on the show.

muppet babies was my favorite show as an kid!!