I am honestly baffled by how much people love firefly. I don't get it. It's a slightly campy western-style scifi. It's not bad but it's not 'still talking about it for the next few decades' material IMO. Theres a zillion littl scifi channel series with essentially the same quality as far as I can figure.
Had it lasted three seasons (or even only two), and still been 'cancelled before it's time' it would have faded from memory more quickly because the itch would have been scratched more satisfyingly.
It was good for it's time, and since it was cancelled it's locked within that time. How it translates against modern television is yet to be seen. However, the popularity of The Mandalorian means there is still a market for the Sci-fi Western.
(I liked parts of The Mandalorian, but it went downhill pretty fast in terms of ... everything. I like the sci-fi western thing - it's not serious, but it can touch serious-ness. The Expanse was serious, and touched some Western/Frontier sci-fi)