It depends on how much those folks will spend to reduce their pain. And then there's the wannabees who you might get to pay for junior versions.

that was me trying to be a smart ass. missed an order of magnitude

the market is about 15000 people

regarding a wannabe / junior version comment I am inclined to think that the tool requires 100% functionality to be useful.

I guess the interesting figure here is the yearly 2 * 3e+9 euros worth of business.