If you don’t care about user adoption (it’s for yourself or a captive audience), then you can have less polish and rely more on training, to an extent. But your tool will be compared with consumer software.
Note the "core part" though. Even professional tools that many people have to use occasionally (say tools to book professional travel) should be intuative because someone who uses it once or twice a year will forget complex things. But it's probably OK for a CAD program used by engineers as a main part of their job to have a steep learning curve.
> I’m not convinced that making interfaces so simple and “intuitive” that anyone can truly learn them on their own is even possible, maybe not even desirable since it encourages more of that kind of rugged individualism in computing
If your software gets the users the training they need, they might be much happier with it and recommend it to colleagues in the field or request it at a future workplace. They'll also know who to ask because they've made contact with experts already
A competing product where everything is made obvious, but also dumbed down and cumbersome in some ways because you are always treated like a beginner, may end up losing out if the training-required one gets their market placement right