You are certainly right. Steemit provide a great road system by which users can travel from one subject or topic to the next. It helps to eliminate the walls that divide health and psychology and chemistry (or any other interrelated fields) and helps facilitate wider content consumption.
I think that SteemSTEM is a great microcosm of this observation, an ecosystem within an ecosystem bringing different minds together.
:)
But is it helping to eliminate the walls that divide health and psychology from say cooking and travel? That is what we need to achieve, and if we are not, what can we change to start making inroads there?
I think that it does, but in a different way. I, for example am planning on posting my travel and politics related content on this account. Thereby all of followers will be exposed to that content, and the other commenters who might have come from #travel. In this way, the users who cross multiple fields will expose their followers to those subjects. But, you do have a point that we should look for other ways to promote cross subject exposure.