Yep, and the barrier to entry follows, IMO, a U shaped curve where a field gets easier to enter past the initial development, but then gets more difficult over

Yep, and the barrier to entry follows, IMO, a U shaped curve where a field gets easier to enter past the initial development, but then gets more difficult over time as it matures and the easiest tasks continually get whittled away, until increasing abstraction of tools requires sufficiently increased abstraction of thought.