Hi @schattenjaeger. First of all: my compliments to you for writing this high-quality post, that I've just read front-to-back (including most of all comments on it) and resteemed as well (which I rarely do).

I don't know about other Steemians, but I take a habit quite often while at a break to read what's on trending on my mobile phone, just using steemit.com in a browser, not logged-in.
9 out of 10 days, I mostly only find total crap posts on Trending; today was an exception day because of your post, and actually it's a shame you had to promote it for visibility / get to Trending, but I'm still glad you did so I noticed it and others do as well.

To answer your request for feedback on:

What are the things, right now, standing between you buying more STEEM?

You didn't explicitly make a difference in your question, but I will:

-Q(a)- what's holding me back to buy more STEEM?

and

-Q(b)- what's holding me back to buy more STEEMPOWER?

My answer on -a- is: timing.
The price of STEEM in terms of BTC sat is currently bottoming after a 6-month downtrend. Chances are high it will soon go up, but it's still not in a clear uptrend. Some other alt cryptos are already. And as soon as STEEM is as well, then nothing is holding me back to buy more.

My answer on -b- is: the 13-week powerdown period and/or lack of other options to immediately convert to liquid - at a cost even! - when needed or otherwise desired.
In case of strong market swings, large SP holders are like sitting ducks where a minority of exchange-held STEEM is dictating prices for everbody on the platform. The SP holders simply cannot move / act on opportunities.
I recently wrote a Platform Proposal Post (that didn't get much visibility platform-wide) in an effort to solve the powerdown period without needing a complete blockchain overhaul. From the responses that did came in, it became clear (to me at least) many more people would actually use their STEEM and also power-up to SP if and when they would be able to get liquid the minute they need it. My proposal discusses an internal market feature where SP can be traded for liquid STEEM (and SBD).

PS1: yesterday was my "Steem 1 year birthday" and to date I haven't bought any crypto nor sold any for fiat money. In the first 10 weeks on the platform, I got lucky that both SBD boomed and STEEM followed suit, while BTC went down: I turned 222 SBD into 0.6 BTC via @blocktrades, because I could not get into exchanges then because I was a "crypto newcomer", many others were as well, and due to all the attention nobody was able to create a new exchange account. Afterwards, I did get in, and having learned about volatility, market psychology / TA, I was able to "invest wise" and I did well.
I could have never achieved the same results if I would have powered up the few SBDs and STEEMS I made via posting - despite the fact I always try really really hard to only publish HQ material, without using promo tools.

PS2: there are more ways than investing a ton of money and power-up to SP to gain "influence" on the platform. UA proves that: even after taking away the WitnessRank sub-algo, the UA data shows that although high-UA strongly correlates to high-SP, there are more ways to gain high-UA scores.

Welcome scipio ! Your ua score is 6.269 and you have a ua rank of 215

I'm not a witness, I don't own a lot of SP, yet I rank 215 on the "influence list". Of course launching @steem-ua increased my influence rank somewhat, but before UA & @steem-ua were launched, I already ranked in the 400-500 UA regions. That alone proves you don't need a ton of SP to have some influence. Doing "interesting things", things that get noticed by others, which could be anything, has an effect on your influence as well.

PS3: why form a "middle-class" and what's the best way to form it?
If you form a middle-class on a platform like Steem, you have a group of people that have at a decent probability the opportunity to grow big and at the same time have an interest to not lose, which is done best by getting in as many other people to join them. Because of such a "middle-class", the entire platform grows and thrives. So sure that's important, I argue.

But I think growing such a "middle-class" group of people on Steem is a task to be completed in the first place by Steemit Inc and the Ninja-mined large-SP account holders: "the whales". After all their interests align most with growing the platform because they own most. Empowering communities such as @utopian-io and @steemhunt with SP delegations is an effective way to accomplish that. I'm sure many redfish accounts would have left long before now if those community accounts weren't powered that much SP to reward their contributors with.
And I'm also quite sure the ninja-mined accounts have taken quite some profits by now, ergo are now probably holding other crypto, which enables them to bring STEEM in a price uptrend at least. Such an uptrend will trigger trading bots to buy more, catalyzing a much higher STEEM price; and as the data clearly shows, the higher the Steem (& SBD price) the more platform activity.

Thanks again for writing such a good discussion-provoking article, please publish more: the platform needs it!
Cheers, @scipio