Certain elements of the interstellar government are technocracies - placed into power because they're skilled, and their skill gains them more power, which they use to ensure their status by being efficient, as their power is used to find and recruit the skilled.
As to "how is a FT different than an autocracy?"
Let's see the table (reformatted, but text unchanged from it's appearance in Starter):
Digit | Title | Description |
0 | No government structure. | In many cases, family bonds predominate. |
1 | CompanyiCorporation. | Government by a company managerial elite; citizens are company employees. |
2 | Participating Democracy. | Government by advice and consent of the citizen. |
3 | Self-Perpetuating Oligarchy. | Government by a restricted minority, with little or no input from the masses. |
4 | Representative Democracy. | Government by elected representatives. |
5 | Feudal Technocracy. | Government by specific individuals for those who agree to be ruled. Relationships are based on the performance of technical activities which are mutually beneficial. |
6 | Captive Government. | Government by a leadership answerable to an outside group; a co!ony or conquered area. |
7 | Balkanization. | No central ruling authority exists; rival governments compete for control. |
8 | Civil Service Bureaucracy. | Government by agencies employing individuals selected for their expertise. |
9 | Impersonal Bureaucracy. | Government by agencies which are insulated from the governed. |
A | Charismatic Dictator. | Government by a single leader enjoying the confidence of the citizens. |
B | Non-Charismatic Leader. | A previous charismatic dictator has been replaced by a leader through normal channels. |
C | Charismatic Oligarchy. | Government by a select group, organization, or class enjoying the overwhelming confidence of the citizenry. |
D | Religious Dictatorship. | Government by a religious organization without regard to the needs of the citizenry. |
Fundamentally? It's the low-pop version...
The government is low enough that the people can be picked for their established skill.
On the Imperial level, that's not quite true.
But note that the other single-ruler autocracies are all minimum pop 4 or higher, while an FT can be generated on a pop of 0-A...
So, being in the middle, it also tends to be a lower law level. Which implies some level of confidence by the governed.
In the case of Aramis - the people there apparently have the right to leave; I suspect HE Leonard would likely offer popsicle passage to anyone unwilling to work and unable to afford to leave, simply because those are the types most likely to become criminals... and it's a "throw some money at it and make it go away" solution to a major social problem.
In practice Aramis (and the 3I) are civil service bureaucracies tied to a semi-feudal oligarchy (the nobles), a portion of which said oligarchy (the enfeoffed nobility) have the right to oversee and intervene. (And the non-enfeoffed ones have sufficient visibility to earn their way into that by use of patronage and obeissance, which while not strictly feudal, mirrors it.
EG:
Guy Richman owns a 7-ship line. He built it from the ground up with a few lucky cargo runs and a lot of hard work, and now is expanding to formal liners. The local baron of his HQ's homeworld puts him forward for a domain knighting. The patronage is noted, the orders are given, and the baron, by let of the Archduke (and the patent therefrom) dubs him Sir Guy.
If he plays by the rules, does well, and makes a name for himself, the Archduke might subinfeudate him, or might nominate him to the Emperor.
If he gets stupid, he gets called before the Archduke, tied up for months in hearings and "special investigations" (some of him, and some unrelated to his business, like mine inspections, by him) while his company is quietly liquidated by covert actions thanks to the Archduke's stocks in various regional mini-megas (such as Oberlindes) and imperial-level megas (Nasiraaka, Sharushid, Hortalez etc), and influence with and authority over the Imperial Bureaucracy. Including IMoT, IMoJ, and the SPA.
See, if the Subsector nobles notice Guy being a jerk, or being too aggressive in his price competition, suddenly, they all approach their Megacorporate agencies, and suggest doing something about him. Meanwhile, they also hit the SPA and IMoJ, and tie him up with slowdowns and inspections that are legal but uncommon... except for him. Fief-worlds simply don't allow him entry to their space. (The SPA doesn't have the authority to clear people to land when their ship's been ordered away by local coacc and/or system navy.) And certain businesses simply slow down his order processing by a day (as in, that "3-5 days" listed is always 5 for him, even tho' it normally runs 3 for everyone else...).
As the hassles build, and the "special duties" accrue, Sir Guy either agrees to change, or goes bankrupt... in the latter case, he might find a place in someone's court as a hanger-on - the Count's Mother's consort, or the Baron's Voice Herald... Or might get stupider still, and brake a law in response to the pressure, and get himself brought up on charges by the Subsector courts. Even specious charges can ruin him.
The FT as described looks to be functionally a civil service bureaucracy that has an oligarchy at the top, whose technical service is Human Resources (for upper management level positions) and Propaganda, as well as long term stability.