Yeah it has really slowed up a bit, for majority of the franchise's lifespan it was one every two years, sometimes consecutive years, and whenever Never Say Never Again came out there was two bond films in one year. it's kind of an odd one really because it's the one series which isn't really changing for modern times and TBH it feels rather old and out of date. That being said the interest is clearly there, Skyfall and Spectre were massive hits way bigger than the few before that.