I felt similarly. Exploring is just another thing to "do" to get credits/nanites. It was cool to see genuinely new things like the huge Dune-styled worms but once you see one you've seen them all.
That extends to base building too. I have no reason to build a base anywhere else in the galaxy once I have a capital ship that does all my crafting for me. Except resource collecting, I guess. But meh, different strokes for different folks. I don't think there's been a non-MMO continually-updated game that I've come back to as often as NMS but coming back is usually pretty short-lived.