1st rate are too cheap but making them more expensive will not diminish their numbers, players will always do whatever it takes to have the best equipment available.
https://postimg.org/image/61vi5mprb/
https://postimg.org/image/h2twpva87/
Above are 2 screenshots 1 before I sold the ship and 1 after, as you can see this action restores me to full crew.
I will put it more simply, before I sold the ship I had the option to hire crew, afterwards I did not, that means I gained total crew. The only way to do that is hire them or use a medkit, I did neither.
There is definitely a bug regarding crew, I just did a 152 fleet mission in a connie, I capped a ren and cerb and sent them back to an outpost to sell, when I docked then teleported to willem I was back to 1100 crew without hiring any crew. I did not take any screrenshots but I will try to replicate it and take some.