Because no one does any actual engineering in space. At best you’re a technician running other people’s projects; at worst, you have to MacGyver something. But every ISS crew needs a medical specialist on it, and a backup specialist in case they need to work on their medical specialist. So it gives you the highest odds.
Now if you wanted to work at JPL designing probes, that’s a different story. But you’re not going to space.
Because no one does any actual engineering in space. At best you’re a technician running other people’s projects; at worst, you have to MacGyver something. But every ISS crew needs a medical specialist on it, and a backup specialist in case they need to work on their medical specialist. So it gives you the highest odds.
Now if you wanted to work at JPL designing probes, that’s a different story. But you’re not going to space.