It could just be me getting older but I feel like action movies these days have action scenes that just go on for an eternity. (I don't know what's wrong with me but sometimes I just want the characters to take a breather and talk about their lives and feelings for a few minutes.) Lately I don't get a chance to see as many movies but the first movie where this really jumped out at me was Indiana Jones 4 and the most recent was Star Wars 7. (After checking IMDb, I cannot believe these two movies were released over 7 years apart!) I feel like both of these movies had action sequences that went on much longer than, for example, Terminator 2.
Am I just getting sensitive in my old age or are action sequences getting longer?
It seems plausible that action scenes are becoming longer since longer action scenes probably sell more tickets and each second of action scene is probably becoming less expensive to produce.
From a quick googling, I found this publication so it looks like there is research on these sorts of topics. If no one beats me to it and posts a strong answer, I'll try to find time to dig into this and see if there's a publication that answers this question.
Update: I haven't been able to find any publications on this topic or even find a way to determine an answer without sitting through hundreds of movies with a stopwatch. However, it still seems very possible that a publication addressing this question or an appropriate dataset for answering it does exist somewhere.