Of course not. But you're not separating the game from reality. That is those people's JOBS. Do you think they'd do it without being paid? Some, maybe. Most? No. Pretty sure I'd stop going to my job if they stopped paying me, and I like my job.
Do you think their job is nothing more than "Push W to go forward", "Right click on rocks to get science"? Every action that rover does will have dozens, if not hundreds of manhours behind it. They have more than their share of stuff to do. They most likely have job duties that involve something other than the rovers. The rovers weren't put on mars by some kid sitting at a computer clicking premade parts together and then just sitting and waiting for months for it to get there.
Because it's their job, it's what they're supposed to be doing at the time. Lets say you send off a rocket to get to the Mun. Takes a few hours to get there. You plan on being at your computer when it gets there. But what if you're not? What if your internet or power is out? What if someone you're playing with is depending on your rocket to do its injection burn and land at the right time, and you're taking out the trash? (Insert link to youtube clip of Brandon taking out the trash in Galaxy Quest that doesn't seem to exist). Do you have backup to jump on your computer and do those things if you can't?
You missing your deadline could cause someone else to waste hours, days, or even weeks. This isn't some matchmade shooter where you can just quit and start a new match when one of your teammates flakes.
Please do not equate real space agency jobs with playing multiplayer in this game.
This is ignoring the fact that people can be *insert not-nice word of choice here* and you could spend all that time landing and starting your base just for someone else to come along and blow it all up, steal it, kill your kerbals, etc. And if you say "Well they can't interact with my stuff", then multiplayer would seem pointless if you don't play at the same time. You'd essentially be passing a save file back and forth with someone you trust, and you can already do that.
Don't get me wrong, I would love multiplayer, if they could somehow make it tolerable without turning it into a freaking war / shooter base that almost every other multiplayer game out there depends on. I already play Halo. I have just never seen an argument for multiplayer that both involves actually going to space and makes sense.