A "steep learning curve" actually means that the amount learnt grows rapidly over time. It's odd how this basically obvious conceptualization has had its meaning inverted in popular usage.
This is one of my pet peeves, as well. Though I have moved on. Colloquially, it is clear how folks take that saying. Just transpose the chart if it helps you think about it.
That is, it may have originated with that meaning. But it is far from unique in having the general meaning shifted with use.
That is, it may have originated with that meaning. But it is far from unique in having the general meaning shifted with use.