Hey @exyle! First of all, I'm glad to see more of these vlogs again, I've missed them! They used to be my daily dose of the Steem blockchain way back when I was getting started (over 1 year ago now)... Wow does time fly!
I love the question you pose here about RCs. I do have a few ideas for the future and how I believe RCs will play a role, this may be long, so here we go:
1). Addressing the concern of new users and people with little to no SP:
I believe (and I know from your vlogs that you do as well) that DApps will become the primary way that people interact with the Steem blockchain and will be the source of the need to transact on the blockchain (SM battles, posts, videos, steepshot photos, etc.). Thus, the DApps (in my opinion) will bear the responsibility of "issuing" RCs to their users. I have a few different ideas for how this may work but what I consider to be the most valid idea is this:
DApps will have a massive need for RCs. They will get their RCs by leasing SP from delegators, buying STEEM themselves and potentially renting RCs exclusively (should an RC delegation option become available, which I think it will). I believe that through a combination of these methods, individual DApps will create their own large pools of RCs from which each user of their specific DApp will draw from for each transaction on the blockchain. There will need to be some sort of system for these users to simply "borrow" the required RCs from the DApp pool in order to make their post - which I think is a likely addition.
Now that begs the question of how the DApps issue out RCs (from their pool) to their users. I believe they'll do this based on the stake that their users have of their token..
Here's an example (using very simplistic numbers): Steem Monsters would issue SM token and determine that anyone with 10 SM tokens grants them access to the RCs (from the Steem Monsters pool of RCs) required to make 10 transactions on the Steem blockchain - in the form of battles, card sales, packs etc.
Each DApp will have their own parameters for the usage of RCs based on how many tokens their users hold in order to keep up with the regeneration of their RC pool versus user activity ratio. I imagine that DApps would actually love this feature because it would cause an added benefit and therefore, an added demand for HODLing their token and will drive the price up.
2). Addressing the question of the cost of actions on the blockchain with a rising STEEM price:
I'm not exactly sure how this would play out, but I'd imagine that an increase in the STEEM price would inherently lead to a decrease in the cost of actions in terms of RCs... The higher STEEM price would mean a higher barrier to entry and thus, a decreased amount of usage of the blockchain by smaller holders and the RC system (to my knowledge) is constantly adapting to the level of usage of the blockchain, so the RC costs would decrease slightly - though I'm unsure of exactly how much it would decrease and if it would at all if I'm right about these "DApp RC pools".
Though, if I am right about the "DApp RC pools", then the need for the individual to buy STEEM is not as prevalent anyways.
To wrap this all up, I like to compare this idea of "DApp RC pools" to an idea that you've mentioned many times in your vlogs about how the Steem blockchain is becoming less and less about the individual creators and users and more and more about the DApps:
If you follow this line of thinking and consider the blockchain to be a 2-layered system:
1. The DApp layer - the DApps are the ones who primarily deal with the issues of RCs, STEEM POWER, and ulimately, interfacing with the Steem blockchain
2. The user layer - the users are using the DApps and therefore, don't interface with the Steem blockchain or RCs/STEEM POWER directly and use their preferred DApps as a sort of "gateway" or "middle-man" to the Steem blockchain itself.
Anyways, those are just some of my thoughts. But damn, that ran way longer than I expected! Please keep it up with the vlogs, I love that you make us all think long and hard about the Steem blockchain! It's very valuable!