why can't you be an authority to teach children about science if you do the work? It's (literally!) not astrophysics. Instead it's just reading and synthesizing a base level of pre existing scientific knowledge and then presenting that in an engaging way to kids.

His popularity (from the kids show stuff) with millennials suggests he was a complete success in that regard.

Why would you need to spend years of your life studying to explain the basics of "the water cycle" or "the planets" or "magnetism" or "the food cycle" to kids?

The guy who created Khan Academy has a masters degree but what if he didn't? If someone goes to Khan Academy to get a better understanding of Calculus the only thing that matters is the ability of the presenter to convey that level of information to the reader.

I'd argue Bill Nye's career as a "scientific communicator" has real value.

I'm not a huge fan of how he's used his legitimately acquired credibility as someone who gets kids really interested in science but that doesn't deminish what he actually did.