I think you are right. If you follow the guidelines and are still not successful, you get frustrated and that is when people quit. It is a game, it is supposed to be fun/entertaining on some level. Yes a challenge can be fun/entertaining, but not being successful time after time, when you are doing your best is not fun. It is not like people are learning anything, the way to mine has been outlined in countless videos and threads.
I personally think the fact that more players have advanced to the point where gem mining is appropriate for the level is combining with the few planets that have the resources and the “new” regen methodology to create the shortages. I think the regen, once it starts has to be speeded up and the distribution has to be increased. If the developers do not want to have to add 3 times the number of gem bearing planets due to server costs, then what else can be done?