The organic demand is exactly what you say, a source of RC. The problem is that the numbers demonstrate clearly that for such demand to support the price in a viable way requires a scale of growth that is probably years away at best and may not happen at all. (Alternately, the price of RCs would have to rise enormously, which we could theoretically arrange by drastically/arbitrarily reducing the resource pool sizes, but this too would kill growth and is not a viable path.)

It is exactly (speculative) investors that fill need to fill this gap by betting on whether that demand will happen some time in the future. There is zero chance that there will be enough demand for RCs in the present directly to support the price, but at the same time if there isn't enough value in the platform to support continued development, support for the infrastructure, etc. then we will never get the chance to grow enough to where it potentially could. Again, it is only investors/speculators who can possibly fill that gap.

Even the original white paper was pretty clear on this. Most of the the demand for Steem in the short term has to come from speculators, not fundamentals. If we make the product unattractive to speculators (and indeed, the original design/white paper got this very, very wrong; it is probably not a coincidence that EOS launched with 2 day lock up and not anything like the 2 years or 13 weeks in Steem), then in the short term, speculators won't buy it, and if they don't (again, in the short term), no one will.

Similar comments can be made about inflation and investability, and likewise relationship to EOS and other newer projects (and older more successful projects) that are better accepted by the market, and so forth, but that's a bit off topic here.