[DANmode]

You become an expert in using SalesForce, or SAP, for the same reason you get a medical license in the US.

There’s a limited number of you who are willing to traverse that gauntlet of abuse, so you know you’ll always have work.

[mrgoldenbrown]

For doctors in the US I think the limit is more artificial than that: a cap on how many med school seats are allowed.

[DANmode]

The captive audience after some (mostly) arbitrary grinding,

(not being drawn to serve the niche by any particular talent or interest besides $),

is the comparison being drawn.