Oh no? Then this statement:
Nodes that are running additional API plugins (especially account history) will require more RAM to support a larger state file.
Certainly isn't congruent at all.
Here's the thing, you're taking one strategy "Put it all in RAM" and substituting "Put it all on SSD and page INTO memory", which doesn't address why you need to do the above in the first place.
The reason you have to split things into "modules" and try to even out the load is that your full nodes using delegated-proof-of-stake will not scale any further without "further optimizations" which right now consists of "offload the stress to cheaper/slower IO device".
Its very similar to the strategies that Ethereum is trying to solve, because their blockchain is bloating way too fast (lots of blocks filled with all kinds of junk, like cryptocats - the faddish pokemon ripoff).
All I'm seeing here is a fire-drill response that will result in short-term relief, but hasn't addressed the fundamental problems that exist.
Its okay, with the retention metrics being consistently crap - I think the only demand you are feeding is that of the bot armies that are diligently sucking the Reward Pool dry.
Its a bit like upgrading your email server because you have a lot of spammers hammering it. It doesn't help anything, because the root problem hasn't been solved.
Sorry, but I think you are misunderstanding some of the technical aspects here. There are two different things being discussed.
If you are talking about DPoS - then you are talking about consensus nodes. These are the nodes that keep the blockchain state updated, and ensure that all of the new blocks are 'valid'. These nodes are covered in the "witness and seed node" section. Everything that is required for the DPoS portion of Steem to run is contained in these nodes, and the post was very clear that these nodes do not require the state file to be stored in RAM.
The part that you are quoting is talking about "full nodes" which get into API calls. API calls are an application layer built on top of the blockchain consensus rules. These nodes require more RAM because of the way the code is currently implemented, but eventually (as stated in the post), this logic for all of the non-consensus API methods will be handled separately - through things like HiveMind, SBDS, and RocksDB.
If your concern is rewards pool abuse and spam - those are valid concerns, but they are not going to be resolved in the context of "addressing the scaling requirements of the blockchain". Fixing spam and abuse issues might slow down the growth - but the ever increasing growth of the blockchain problem will still always be there - so scaling is something that still needs to be addressed regardless of what is/isn't done to address spam and abuse.
It seems we've reached the TTL for this convo, which is fine.
See you in a year, if this is even still around. Then we'll talk.