That's trivially false. There's a large difference between products designed primarily to have a low learning curve, and products designed to maximize the efficiency of users that have been trained in its use.
The only products which should have any mandatory learning curve are products which actually allow an expert to do something out of the ordinarily, which simply could not be done with an easy to use product. Such as some musical instruments.
Otherwise, you can most of the time make a product which can be easy to use for novices while retaining maximum efficiency for experts.
Compare a professional trader's UI to something consumer-grade like Robinhood, or analytics UIs designed for marketers (exposing only a few cute graphs with a handful of predefined parameters) to the dashboards used in physics labs, or simple graphics programs vs. Blenders.
Maximum efficiency for experts requires removing information that would be distracting and redundant for them, but essential for novices to understand the working model of the program, so you're pretty much wrong.
