Moon Druid power tends to drop off drastically after level 6. Level 2 is the high point of the Moon Druids career, level 9 is a low point it gets a little bit better at 10 and then it is all downhill. At level 14 you almost suck in animal form and the elemental forms do not really do that much damage.
Form the DM PoV you just ignore the moon Druid as beating on them is kind of what they want. Their accuracy in animal form trails off and so does the damage and all they have left is really a bag of hit points. THe land Druid will likely out damage them and be useful casting spells while moon druids tend to use their as spell slots to heal themselves which I am not convinced is the best thing to do with them.
Except at higher levels, a Moon Druid can pull in conjured animals (or an even more powerful conjured creature like an elemental or fey who might have spells and such) in every single encounter. Just because their Wild Shape ability starts falling a bit behind does not mean that the class gets weaker. The class evolves.
From an action economy POV (even if the NPCs ignore the conjured creatures and provoke OAs from them in order to get to the PCs), a Moon Druid can be doing many attacks per round via conjured creatures and can definitely control a battlefield. Granted, some things like resistance can weaken the damage of conjured creatures, but this is not something that NPCs can always just ignore.
Alternatively, they have a lot of other spell options. Confusion, Wall of Fire, Polymorph, Insect Plague, Reverse Gravity. Planar Binding (especially in higher level slots).
Take Tsunami for example. In many cases, that could be an encounter ending spell. Not primarily because of the damage it does, but because of the battlefield control. Not many 8th level spells have this level of action economy shift.
Or Transport Via Plants. Sure, it's a spell level (i.e. two actual levels) after the Wizard can get (but probably won't get) Teleportation Circle, but it's tons more versatile (large finite number of destinations vs. 2 starting destinations).
Druids seem extremely versatile to me. Healing, battlefield control, debuff, buff, damage dealing, damage sponge, scouting (eventually with flying), stealth. I'd much rather have a PC Druid shape change into a Hawk instead of relying on a Hawk familiar from a PC wizard. The former is much more capable of scouting and making good decisions while doing so.
I also find it interesting that some people seem to think that Moon Druids mostly shapechange and Land Druids mostly cast spells. Not the case.