They need to keep training spots where they are... a good rule of thumb is do the opposite of what is recommended by workforce studies. Look at GI and cards - there were workforce studies in the 90s that projected an oversupply of GI and undersupply of cardiologists. The governing bodies then implemented changes as a reaction to these projections by cutting GI spots and increasing cardiology spots. Now fast forward twenty years. The cardiology job market is tighter than Kim Kardashian's yoga pants, and GI is the new gold rush.
Honestly, if you get rid of fibromyalgia as a condition that we treat, there is barely any shortage of rheumatologists.