A lot of 20 year patents on FDM have expired within the last 5-10 years. Technology that was only affordable to R&D labs and university have made it to the end user and experimenters. More hands in the pot means more diverse ideas. Expertise isn't cloaked in NDAs but published in wikis.

I'd say the real hype cycle for FDM was in 2013-2015, as evidenced by the SSYS stock price [1] (many other 3D printing companies have similar curves).

I think we're now on the tail end of the hype cycle graph and people are starting to find real uses for FDM

[1] https://www.google.com/search?q=ssys+stock (set to max time)