The Hobbit -> LoTR

Why did it take sooo long in between the Hobbit and LoTR?? I’ve watched the movies many times and have just purchased the books to read for the first time, but what I can’t understand or get from reading is the timelines. The white council and such knew knew that Sauron was trying to come back to full power, so why did they apparently not seem to do much in the ~70 years in-between? Gandalf was trying to find info on the ring yes but that was after Bilbos 111th birthday, they seeming just were complacent from my point of view, what were they doing, did they hope it was just over and were chilling?? What was Gondor doing in this time, did they know what was happening? I’m just confused why Mordor was able to amass such an army but everyone else just did nothing really?

TLDR: What was everyone doing in the gap between the Hobbit and LoTR, seems like they didn’t care about everything that happened??