They are resource intensive because they prioritize feature completeness over being sleek and lightweight. That's the correct thing to prioritize because, because extra RAM is dirt cheap compared to benefit of higher developer productivity.
That's the point, they already were feature complete back when they were less bloated. VS2017 offers very little over VS6.0 or VB6, I think they're min requirements were 128MB of RAM, it was a lot more responsive too. Similar for eclipse.
Developer productivity hasn't improved since, even gone backwards in some ways.
