ESA mission doing better than NASA's missions

Back in 2009, the European Space Agency (ESA) launched a mission named Soil Moisture - Ocean Salinity, with the acronym SMOS.

It's been doing quite well, going into its fifth year in space.  It provides soil moisture data with a resolution of 35 km in the center of the scan, 50 km overall.

This is the mission site (with links to recent news):
Observing the Earth (SMOS)

On the other side of the pond, NASA launched the Aquarius satellite, to measure ocean salinity, on June 10, 2011.  It worked great, until it quit working, on June 18, 2015.   Just over four years.

302 days ago, according to the Web site on the day I write this, NASA launched the Soil Moisture Active Passive (SMAP) mission, to measure soil moisture, at high resolution with the active radar part of the mission.  Well, I just recently learned that the active part is inactive.  The highly powerful and highly cool circular radar is defuncto, as of September.

NASA Soil Moisture Radar Ends Operations, Mission Science Continues

That cool radar system provided soil moisture data with a resolution of 9 km -- while it lasted.  The passive side of mission, a radiometer that's still working, gives soil moisture data with a spatial resolution of 40 km -- about the same as SMOS.

So right now, ESA's single mission to do both measurements is doing better than NASA's two missions that each did only one measurement.

Now, I'm not writing this to compare ESA to NASA.  Sometimes NASA missions last longer or do more things than ESA missions.  What I really want to say is why can't somebody figure out a way to fix these expensive things when they break in space?  We managed to do it a couple of times, for Solar Max and the Hubble, the latter partly because it was designed to be fixed and updated by astronauts, and because it was in a serviceable orbit.   Note that the highly expensive James Webb Space Telescope won't be.

But what would that take - to fix satellites in space?  Well, one thing that has been proposed to deal with BIG pieces of space junk (i.e., dead satellites) is a "tug", that could grapple onto it and send it Earthward (hopefully oceanward), to get it out of orbit before something catastrophic happened to it and it broke into lots of little pieces, which is bad.

Why not build a slightly better space tug, capable of bringing the expensive satellites down to ISS orbit and in proximity to the ISS, and then let the astronauts go out and fix it, and then let the tug push it back up?  The tug could have an ion engine, so it wouldn't be real fast (obviating the need for lots of maneuvering fuel), but it could substantially extend the missions of these valuable investments.

Wouldn't it be worth it?