Probably because they already sent Huygens and there's planets and moons that haven't been landed on yet at all (i.e. almost all of them). Titan's one of the rare exceptions.

List's actually shockingly short: https://en.wikipedia.org/wiki/List_of_landings_on_extraterre...

Because we burn our space budget on useless and expensive human spaceflight, in the false belief that only manned missions can get the public excited about space.

Historically, just getting anything to another planet costs in the hundreds of millions of dollars. Perseverance launch alone cost $243 million (total mission cost was $2.7 billion). It is an enormous expenditure.

You might be interested that Rocket Lab's Electron now can launch small interplanetary spacecraft for low-eight figures (~$10 million for the launch to lunar orbit for NASA CAPSTONE, https://en.wikipedia.org/wiki/CAPSTONE#Launch).

However, the Electron payload capacity is small (a few hundred KGs). I doubt it is enough for much equipment, but I believe a camera/radio/parachute is feasible. Take these prices with a big grain of salt, as I am just a hobbyist, but now you can get a spacecraft to an interplanetary body for probably around $20-$30 million dollars. As costs fall and other next-gen rockets become operational, I am hopeful that we see more interplanetary landings over the coming decades.

(disclosure, I am a RKLB shareholder.)

I think drilling miles under ice is a mission most likely to fail on our first attempts. It’s the one project I want done but know it might not even happen in the next 50 years.