[Matata]

The nudity was becoming a running joke about the show, plus the climate of Westeros changes significantly over the show, it started the series a relatively peaceful, happy kingdom enjoying the abundance of a prolonged summer, to the frozen, fractured, war-torn hell-hole we know now. It's a lot harder to get laid in the latter and only lends itself to the brutal rapes that are largely left off camera. All in all, there's a lot of good reasons there's less boobies on the show.