If congress doesn't change something, then that means they have determined no change is necessary.
That isn't an invitation for the executive branch (or judiciary) to overreach.
In theory congress could go years without passing a single law, and that would be fine. It would signal that the current laws are sufficient.
(As an aside, congress has ceded much of it's lawmaking authority to federal agencies anyway -- so even if they didn't pass any new laws, the legal code will still change every year.)
That isn't an invitation for the executive branch (or judiciary) to overreach.
In theory congress could go years without passing a single law, and that would be fine. It would signal that the current laws are sufficient.
(As an aside, congress has ceded much of it's lawmaking authority to federal agencies anyway -- so even if they didn't pass any new laws, the legal code will still change every year.)