Suspect that parts of the reason would correlate to periods where the US was more isolationist, and thus didn't replace decommed ships as quickly. That, and while it's a name with a lot of history, the 'biggest' one was the WWII one, so most of those dormant periods weren't screaming out for a new Enterprise.
Only a 14 year period between the WWII Enterprise and the current (due to be decommed) carrier. With time required to design and build the new class, plus it being in a post-WWII period that had lots of ships that were kinda surplus, that's pretty much as soon as it came time to name a new one. Not really a gap there.
Coming up next year is the first real gap where there's now a history of it being an honored namenand not being an active ship. And it'll likely resolve itself as soon as there's an opportunity. They announce names well in advance of making the ships, so there's a backlog of announced ships that haven't been completed yet, so might be a bit to work through to needing more names.