A decorators proposal (and it was a different one than what Google was building stuff off of in 2019) didn't make it to Stage 3 until 2022 (and still hasn't made it to Stage 4).
This also contributed to the idea for years that Web Components were more complicated to support in non-Google browsers or without complicated build processes.
alt Hacker News
Lit 1.0 used non-standard decorators in 2019: https://lit.dev/blog/2019-02-05-lit-element-and-lit-html-rel...
A decorators proposal (and it was a different one than what Google was building stuff off of in 2019) didn't make it to Stage 3 until 2022 (and still hasn't made it to Stage 4).
This also contributed to the idea for years that Web Components were more complicated to support in non-Google browsers or without complicated build processes.